Despite the Dornish staying away from most affairs within the Seven Kingdoms, Prince Oberyn Martell and his lover/paramour, Ellaria Sand, have traveled north from Dorne to the capital of King’s Landing, as King Joffrey Baratheon’s wedding is days away. On the outskirts of the city, the king’s uncle, Tyrion Lannister, is sent to welcome Oberyn’s older brother, Prince Doran Martell, to the capital, the leader of House Martell. However, Tyrion is informed by a Dornish bannerman named Lord Blackmont that Prince Doran's declining health prevents him from leaving the Dornish capital of Sunspear, and therefore he has sent his brother Oberyn to attend the wedding in his stead. Blackmont also informs that Oberyn went ahead and entered the city before dawn. Assigning the reception of the Dornish lords to the City Watch, Tyrion informs the sellsword Bronn that they should find Oberyn as soon as possible "before he kills somebody or several somebodies." Along the Street of Silk in King’s Landing, Prince Oberyn and his lover Ellaria are examining prostitutes in Lord Petyr Baelish’s brothel, currently managed by Olyvar. When Olyvar calls Ellaria "my lady," she calls him out for using a lie to address her and tells him to call her what she is: a bastard. The Dornish couple choose a contortionist named Marei, and Oberyn then orders Olyvar himself to get undressed also, revealing a sexual fluidity that is common with Dornish people. Their escapades are interrupted, however, when Oberyn overhears men singing the infamous House Lannister victory song "The Rains of Castamere" in the next room. Ellaria tries to stop him but can only watch as Oberyn takes out his rage on the Lannister men-at-arms, who insult him and Ellaria. Oberyn moves closer and chastises them for being "pink little men who are far too slow on the draw." One of the soldiers reaches for his sword, and Oberyn quickly stabs him through the wrist with a dagger and tells the other that his friend will only live if he immediately gets help. Amidst the confrontation, Tyrion and Bronn enter, defusing the situation. After introducing Ellaria to Tyrion, Oberyn steps outside to speak privately with the Lannister dwarf. Tyrion asks Oberyn why he came to the capital, as Oberyn lazily dodges the question by confirming his invitation to the royal wedding. However, Tyrion knows he's lying and asks for the honest truth. Oberyn then informs that he remembers how Prince Rhaegar Targaryen wed his sister Elia Martell, and how his involvement with another woman, Lyanna Stark, was the catalyst that started Robert's Rebellion. He adds that the war ended with Tyrion’s father, Tywin Lannister, sacking the city while Ser Gregor Clegane brutally murdered Elia's children, then raped and murdered her. Oberyn orders Tyrion to tell his father that he's arrived and then warns him that “the Lannisters are not the only ones who pay their debts.”

Days later, King Joffrey and Queen Margaery's wedding ceremony takes place in the Great Sept of Baelor conducted by the High Septon and they are wed in front of gods and men. After the ceremony, the royals gather outside the Red Keep for a lavish wedding feast in celebration of the union of House Lannister and House Tyrell. Walking towards the feast, Lord Tywin Lannister and Lady Olenna Tyrell discuss the extravagance of their union between their grandchildren. Meanwhile, Prince Oberyn and Ellaria greet Tyrion upon their arrival to the feast. Along the royal banquet table, Lady Olenna then speaks to Sansa Stark and offers condolences over the recent Red Wedding massacre that resulted in the deaths of both her mother and brother, Lady Catelyn and Robb Stark. Olenna invites Sansa to visit her home of Highgarden some time when things settle down. During the exchange, Olenna toys with the girl’s hair and necklace in a grandmotherly fashion. After King Joffrey and Queen Margaery watch a group of minstrels play the Lannister song “The Rains of Castamere,” Margaery then rises to announce the leftovers of the large feast are to be given to the poorest in the city, which is applauded by the court. The king’s mother, Cersei Lannister, playing her part through gritted teeth, informs Margaery that she is an example to them all, though her dislike for the new queen is well-known.

During the feast, Prince Oberyn eyes the queen’s brother, Ser Loras Tyrell, with an obvious flirtation, to which Ser Loras intriguingly reciprocates. Loras then accidentally bumps into Ser Jaime Lannister as he stands in his spot as Kingsguard. After an apology, both knights talk about Lord Tywin’s arrangement of Jaime’s sister Cersei to wed Loras. However, Jaime informs Loras that he will never marry Cersei and that she would kill him and any child conceived on their wedding night. Loras replies that neither will Jaime, a subtle barb to their not-so-secret incestuous relationship. Afterwards, Prince Oberyn introduces Ellaria to Lord Tywin and his daughter Cersei, who subtly mocks Ellaria’s status as a bastard, instigating a debate over the cultural differences between the Dornish and the rest of Westeros. Ellaria seethingly states that there are bastards everywhere in Dorne. During this conversation, Oberyn makes a subtle comparison between the Lannister's ill treatment of his sister Elia's deceased children and the Martell's exemplary treatment of Cersei's daughter, Myrcella Baratheon, who has been safely living in Dorne for several years now, as she has been arranged to wed Prince Doran’s son, Trystane Martell. King Joffrey then interrupts the tense moment and speaks to the court about contemplating history. Five dwarves then ride out of a large golden lion, dressed as and representing Joffrey, Renly Baratheon, Stannis Baratheon, Robb Stark, and Balon Greyjoy, each of the five kings in the War of the Five Kings. The dwarves put on a performance, jousting, fighting and making crude sexual acts which cruelly entertains Joffrey and Cersei, though is found too confronting by most of the court, including Oberyn, Ellaria and Queen Margaery, who watches her king with disdain. Sansa Stark makes little effort to hide her disgust during this satirical performance of the death of her brother Robb, as the dwarf portraying the late king parades around with a direwolf’s head. Ser Loras Tyrell leaves in anger after watching the crude depiction of his deceased lover Renly riding a mount that resembles himself. Once finished, Joffrey expresses his delight with the play and prepares to give the champion dwarf a purse, but then mockingly suggests that his uncle Tyrion should fight him as well. Tyrion cleverly counters this jape by suggesting that Joffrey should fight instead and show the same bravery he displayed at the Battle of the Blackwater, cautioning his nephew to be careful as the champion dwarf is "clearly mad with lust" and it would be a tragedy for the king to lose his virtue hours before his wedding night. Enraged and humiliated that his uncle outwitted him in front of his wedding guests, the king petulantly pours wine over his uncle's head and orders Tyrion to serve him wine as his cupbearer. Tyrion approaches Joffrey, who then purposely drops the goblet and kicks it under the table. Sansa hands the goblet to Tyrion, and he fills it with wine and hands it back to Joffrey. Oberyn and Ellaria witness the king demanding Tyrion to kneel before him but Tyrion refuses. Queen Margaery quickly interrupts the tense moment and informs that it is time to cut the pigeon pie. Joffrey then hands the goblet to Margaery, who then places it at the edge of the table near her grandmother Olenna. The king then draws his new sword, cuts the pie, and several white doves fly out. Sansa and Tyrion attempt to leave the feast but Joffrey commands Tyrion to serve him wine to wash down the pie. Tyrion hands the goblet to Joffrey and he quickly drinks all of it. Joffrey then tries to speak but begins coughing as he grabs his throat, while Margaery exclaims that he is choking. The king collapses face down and begins vomiting and convulsing, as Ser Jaime and his mother Cersei rush in and turn Joffrey over on his back. A former knight named Dontos Hollard then suddenly approaches behind Sansa and urges that she must escape with him now. Oberyn and Ellaria watch the Lannister siblings hopelessly hover over their dying son, as Joffrey then points an accusatory finger in Tyrion's direction, as Tyrion examines the wine goblet. Joffrey's eyes turn red while blood runs from his nose. The king then stops convulsing and dies in Cersei’s arms, who sobs with grief. In front of the royal court, she frantically orders her brother Tyrion’s arrest for the poisoning of her son.

Some time later, Lord Tywin interrupts Prince Oberyn, Ellaria, Olyvar and two prostitutes in order to discuss his son Tyrion's upcoming trial for the murder of King Joffrey. Once in private, Tywin brings up Oberyn's knowledge of poisons and the link between that and Joffrey's death, wondering whether Oberyn had assisted Tyrion. The topic quickly changes to the murder of Oberyn's sister Elia Martell by Tywin's "pet," Ser Gregor Clegane, during the Sack of King's Landing. Lord Tywin denies ordering her death, but promises to arrange a meeting between Oberyn and “the Mountain” so he can have his justice. He also offers Oberyn a position on the small council, if he agrees to act as the third judge during Tyrion's trial. Tywin explains that he is eager to bring Dorne back into the fold, wanting to unite the Seven Kingdoms against more obvious threats; citing that the Greyjoys are in open rebellion, a wildling army is advancing on the Wall, and Daenerys Targaryen is in the eastern continent of Essos with three dragons and building a powerful army. Tywin observes that only the Dornish successfully resisted Aegon Targaryen's dragons during his invasion of Westeros three centuries ago. Oberyn dryly notes it must be hard for Tywin to admit he needs the Dornish for help. Tywin admits that they need each other, who adds that he will help serve justice for Elia’s murder.

Several weeks later, following Tyrion’s trial for the murder of King Joffrey, Tyrion maintains his innocence. However, knowing a fair trial and appropriate justice will not be served to him, Tyrion demands a trial by combat. Later, in his cell, Tyrion is approached by Oberyn Martell, who informs the dwarf of his disappointment in their first encounter as children. Oberyn and his sister Elia were told stories of the "Lannister Monster" and his extreme deformities. During a childhood visit to Casterly Rock, his cruel sister Cersei showed off Tyrion with great ceremony. Oberyn tells Tyrion that he saw no monster, just a baby, adding that he and Elia were quite disturbed at Cersei's strong hatred toward Tyrion from such a young age. Tyrion’s eyes begin to tear, as he’s always been disturbed of Cersei’s hatred. Oberyn then tells Tyrion that he seeks justice for the death of his sister Elia, as Tyrion replies, "You are in the wrong place." Oberyn counters that he is in the perfect place; all those he means to bring to justice for his sister's murder are close at hand. Intending to start his revenge with Gregor Clegane, the knight who killed his sister, Oberyn offers his service as Tyrion's champion in the coming trial by combat.

Days later, Lannister guardsmen escort the shackled Tyrion to the arena, where a large crowd has assembled for the trial by combat. Tyrion grows apprehensive to find a helm-less Oberyn drinking, and wearing very light armor – in comparison to his opponent Gregor, who is clad in heavy armor. Oberyn dismisses Tyrion's concerns, noting that he always drinks before a fight and favors speed over protection. As Gregor makes his way to the arena, Ellaria becomes concerned, noting that he is the biggest man she's ever seen, but Oberyn  remains confident that he will emerge triumphant. She pulls Oberyn into a passionate kiss and warns him not to leave her alone in the world. After impressing the crowd with a display of acrobatic spear maneuvers, Oberyn goes on the attack, stabbing out at Gregor and constantly moving out of the knight's reach, forcing Gregor to tire himself out chasing his opponent. As he evades Gregor, Oberyn repeatedly taunts Gregor by consistently announcing his part in the murder of his sister and her children, demanding a confession, which only enrages Clegane further. As the “Red Viper” starts winning, Ellaria and Tyrion both witness with relief when Oberyn pins Ser Gregor to the ground with his spear. Their hopes, however, are quickly shattered in the moment when Gregor knocks Oberyn down and crushes his head in with his are hands, to the sound of Ellaria’s agonizing screams. With his fate sealed, Tyrion is struck with horror, as Lord Tywin states that the gods have made their will known and Tyrion is sentenced to death. Ellaria and Tyrion both stare in catatonic astonishment at Oberyn's skull-crushed corpse.

Some months following the brutal death of her lover Oberyn, Ellaria stares out into the lush courtyard of the Water Gardens of Dorne. Still in mourning, she disdainfully witnesses Prince Doran’s son Trystane with Cersei Lannister’s daughter, Princess Myrcella, as they affectionately walk through the gardens together, very much in the throes of young love. Ellaria then rudely demands an audience with Doran, the wheelchair-bound Prince of Dorne. His bodyguard, Areo Hotah, blocks her path, yet Doran tells him to let her pass. She bitterly informs the prince that Oberyn’s daughters, the Sand Snakes, will avenge their father’s death while his own brother, Doran himself, sits in his chair and does nothing. Ellaria then asks to take Myrcella so that she can send the princess piece by piece to Cersei as revenge for Oberyn's murder. Doran refuses, reminding her that, although he loved his brother, Oberyn had participated in a trial by combat, and therefore his death was legal, and not murder. He states that Dorne will not stoop to the level of mutilating children while he rules, even if Oberyn’s daughters, who are trained fighters, side with Ellaria. Sneering, she rhetorically asks Doran how long he expects to rule for, before storming out. Doran and his bodyguard exchange a look as she departs, the latter meaningfully indicating his axe, but Doran shakes his head and returns his attention to the Water Gardens as he contemplates his next move.

Meanwhile, in King’s Landing, Cersei Lannister is still dealing with the fallout of her father Tywin’s murder, as well as the escape of her brother Tyrion, who vengefully shot his father with a crossbow before fleeing to the eastern continent of Essos. Cersei summons her twin brother Ser Jaime to their late father's office in order to reveal a "gift" that was sent from Dorne. As Jaime opens the metal box, he finds inside an ornately carved viper, with a unique Lannister pendant suspended from its fangs. Cersei informs that there are only two pendants like this in the world, the one that is around her neck and the other that was given to their daughter Myrcella. She insists it is a threat against Myrcella, a conclusion Jaime can't refute. Cersei is both unnerved yet not surprised by the threat. She then lashes out at Jaime for not being a father to any of his children, to which he obviously points out that if he had been, their children would be stoned in the streets as a product of incest. Acknowledging Cersei's distress, Jaime makes a promise: "I'm going to Dorne. And I'm bringing our daughter home." Jaime then exits the office with his promise to fix the situation with House Martell.

Some weeks later, along the coast of Dorne, Ellaria races on horseback to meet with the Sand Snakes, three of Oberyn’s bastard daughters: Obara Sand, Nymeria Sand and Ellaria’s own daughter Tyene Sand, the youngest of the trio. Ellaria informs them that Prince Doran will not raise the Dornish army to avenge his brother's death. They worry that they have no army to march against the Lannisters, but Ellaria urges that they don't need one to start a war, all they need to do is kill Cersei's daughter Myrcella. Obara then points out that they may have a problem with this, as a Pentoshi ship captain informed her of Jaime Lannister’s recent arrival in Dorne. The Sand Snakes, however, were insulted that he wanted to be paid for such vital information instead of offering it freely, so they took him prisoner. Nymeria uses her whip to knock a bucket over to reveal the ship captain positioned neck-deep in the sand with his face covered in scorpions. Ellaria and the Sand Snakes realize that they are now in a race against time to see who can take PrincessMyrcella from Doran first. Ellaria asks if the three girls are with her, knowing this will bring Dorne into war. Nymeria and Tyene confirm, while Obara then recites something her father Oberyn once told her, "We all must choose our battles, and the gods let us choose our weapons." She then throws her spear, which quickly impales the ship captain's head. With this, Ellaria’s plan for revenge is further set in motion.

Some time later, in disguise as the Dornish army, Ser Jaime and his accomplice Bronn approach the Water Gardens in Dorne, as Bronn wonders what Jaime will do once they get inside and find Princess Myrcella, to which Jaime replies that he likes to improvise. Meanwhile, Ellaria and the Sand Snakes are already in position within the gardens, as Ellaria sends Oberyn’s daughters to abduct Myrcella, telling them to do it "for Oberyn." Myrcella herself is enjoying another stroll with her betrothed, while Trystane's father Doran and his bodyguard Areo Hotah watch from above. Doran comments that they look lovely together, but that they don't realize how dangerous their betrothal is. Doran asks if Areo remembers how to uses his longaxe, and Areo assures him that he does. Jaime and Bronn infiltrate the gardens and come upon Myrcella kissing Trystane. Jaime then tries to convince Myrcella to come with him, but Trystane interferes, suspicious of the bloodstains on their Dornish robes. When Trystane tries to draw his sword, Bronn quickly knocks him down as Jaime tries to lead Myrcella away, but they are suddenly attacked by the Sand Snakes. Bronn fights against Tyene and Nymeria, while Obara attacks Jaime with her spear, driving him away from Myrcella. Obara orders Nymeria to break away from Bronn and take Myrcella prisoner, but as Nymeria tries to pull her away, they are cut off by Areo and Doran’s other guards, who surround them and force them all to drop their weapons. Ellaria and the Sand Snakes are all then taken into custody alongside Jaime and Bronn.

Weeks later, Jaime Lannister is escorted into the main apartments of the Water Gardens by Areo Hotah, to be received by Prince Doran in a luxurious solar, alongside Ellaria, Trystane and Princess Myrcella. Doran asks Jaime why he has snuck in to Dorne in order to bring Myrcella back to King's Landing. The Lannister knight states that he feared for his daughter’s safety, explaining that they received a threat with Myrcella's pendant in the mouth of dead viper. Doran glares at Ellaria, as Jaime asks if he intends to behead him. Doran says that he will not, because he wishes to avoid war and offers a toast to the new king, Tommen Baratheon, Myrcella’s brother. Ellaria pours her wine on the floor in disgust, as Doran insists that he cannot disobey his king. Myrcella will return to the capital and his son Trystane will go along with them, to take over the seat on the small council which was once granted to Oberyn. Ellaria gets up to leave and states that it is no wonder Doran cannot stand, because he has no spine. Doran threatens Ellaria on her way out if she is to talk to him that way again. Jaime then asks what fate will befall Bronn, who is still imprisoned, and politely insists that Bronn was only following orders. Trystane agrees, saying he has learned the value of mercy from his father, but that he has one "condition." Areo then escorts Bronn to the solar, who apologizes to Trystane when he sees him, saying he didn't mean anything by hitting him before. Jaime then gladly informs Bronn that the Martells agreed to let Bronn go with Jaime, but on one condition. Wordlessly, Areo then delivers it by striking Bronn in the face with his elbow so hard that Bronn is knocked to the floor.

Afterwards, in the courtyard, Areo brings Ellaria and the Sand Snakes before Doran, who gives Ellaria an ultimatum: she can either choose to swear allegiance to him or she can choose death. Restraining tears, Ellaria kneels and kisses his hand. Doran states that he believes in second chances and she is forgiven - but sternly warns her that he does not believe in third chances. Ellaria then finds Ser Jaime in a study writing a letter back to King's Landing informing of his return. Ellaria notes how odd it is that she and Oberyn were looked down on for their sexuality in the capital, and Jaime himself is scorned for his incestuous love for Cersei, though a hundred years ago, if his name were Targaryen, no one would have blinked an eye at such a relationship. Cryptically, perhaps spurred by Doran, Ellaria then states that she knows "your daughter" had no part in what befell Oberyn, and maybe even Jaime is innocent of that, as Oberyn volunteered for the trial by combat. Ellaria then exits, and Jaime is left to ponder what seems to be an apology.

Some time later, along the docks of Sunspear, Trystane and Myrcella bid their farewells to Doran, Ellaria and the Sand Snakes, as they begin their voyage from Dorne towards King's Landing. Upon saying goodbye, Ellaria kisses Myrcella on the lips, while Ellaria’s youngest daughter Tyene shamelessly flirts with Bronn. After departing and onboard the ship, Myrcella and Jaime talk about arranged marriages, as Jaime states his approval of Trystane, finding him to be a nice boy. He then begins to come clean to Myrcella, awkwardly telling her that you “cannot choose who you love.” Myrcella then reveals that she knows that Jaime is her real father, something she believes she’s always known deep down, and that she is glad that he is. As they properly embrace for the first time as father and daughter, Myrcella’s expression suddenly changes when the smile fades on her face and her nose starts to bleed. A terrified Jaime holds her in his arms after she collapses to the floor, convulsing. Meanwhile, still standing on the docks, Ellaria and the Sand Snakes watch the vessel sailing away in the distance. Ellaria then wipes a thin stream of blood from her nose and drinks an antidote for the poison that is coated on her lips. They head back towards the city with a look of retribution on Ellaria’s face, as the Martell-Lannister rivalry reaches new heights.

Some weeks later, Cersei Lannister is sitting alone in her quarters in the Red Keep of King’s Landing when she is alerted to her brother Jaime’s return from Dorne. She excitedly runs down to the port to meet her daughter Myrcella for the first time in the space of almost four years. From afar, however, Cersei’s worst fears are realized when she sees a despondent Jaime standing alone on the boat, with a covered corpse behind him. Immediately realizing the corpse is Myrcella's body, Cersei begins to well up with tears. Afterwards, Jaime comforts Cersei in her room, as she admits to Jaime that she believes their children's deaths truly are destined according to a prophecy she received as a child, since both Joffrey and Myrcella are now gone and the only one left is King Tommen. Jaime brushes this off, insisting that they are the only two who have ever mattered and promising they will take back everything that has been stolen from them. Aware that Doran Martell had nothing to do with Myrcella's murder, Jaime sends the Dornish prince a letter demanding the heads of Ellaria Sand and the Sand Snakes.

Later on, in Dorne, Ellaria helps Prince Doran get to his wheelchair, as they both reminisce about the deceased Oberyn, with Doran stating how much he envied his late brother for the adventurous life he’d led. Ellaria asserts that Doran would have made a bad adventurer, while Oberyn would have been a bad ruler. After settling into his chair, Maester Caleotte brings him a message from King’s Landing informing that Princess Myrcella has died. Before he can even give an order, Ellaria’s daughter Tyene stabs Doran’s bodyguard Areo Hotah in the back, killing him. A stunned Doran is further surprised when Ellaria then stabs him in the chest. After falling out of his wheelchair, he lies on the floor and his remaining guards do nothing, indicating they have sided with Ellaria in the war against the Lannisters. As she twists her knife into Doran, Ellaria informs him that he remained passive despite the brutal deaths of both his siblings, and that the people of Dorne are with her now. Doran begs Ellaria to spare his son Trystane, who has sailed to King’s Landing, but Ellaria coldly scoffs at him. Doran then dies in a pool of his own blood. Meanwhile, as Trystane paints an eye-stone for Myrcella’s funeral on his private ship docked outside of the capital, Obara and Nymeria surprise him with their arrival, as they announce their intention to kill him. Nymeria offers the startled Trystane the choice of which one he'd like to fight. As he then readies to fight Nymeria, Obara suddenly impales him through the back of his head with a spear while his back was turned. As they leave, Nymeria calls Obara “a greedy bitch.”

Several weeks later, Cersei has exacted revenge on those physically closest to her in the form of organizing the explosion of the Great Sept, resulting in the deaths of many in the royal court who acted against her, including Queen Margaery and her brother, Ser Loras. This monstrous act also resulted in the suicide of her last living child, King Tommen. After receiving word of Cersei’s treachery and subsequent coronation as the new queen, Ellaria and the Sand Snakes meet with Olenna Tyrell in Dorne, who is now in mourning after the death of her family. The “Queen of Thorns” quickly shuts down the Sand Snakes' attempts to speak, insisting that the “grown women” are to converse. Ellaria suggests that they must work together for survival, as Cersei has declared war on both of their factions. Olenna expresses her distrust of Ellaria for orchestrating the murders of Prince Doran and Trystane, the brother and nephew of the same man whom Ellaria sought to avenge. Despite this distrust, Olenna then clarifies that the future of House Tyrell has been taken from her, adding that survival is not what she is after now. Ellaria then promises that an alliance will give Lady Olenna her new heart's desire. When Olenna sardonically asks what that is, Ellaria states that it is "justice and vengeance." At that moment, a former advisor to King Joffrey reveals himself. Lord Varys rephrases Ellaria’s statement by saying "fire and blood,” the motto of House Targaryen, indicating an alliance with the dragon queen Daenerys, who is currently sailing to Westeros with intentions to invade.

Some time later, Daenerys Targaryen arrives in Westeros and reclaims her ancestral seat on the island of Dragonstone. Shortly thereafter, she arranges a meeting with the leaders of the great houses she is now allied with, who include Ellaria, Lady Olenna and Yara Greyjoy, alongside her brother Theon Greyjoy. Amidst discussion, an argument breaks out between Ellaria and Tyrion Lannister, who joined Daenerys’ fight against Queen Cersei once he arrived in Essos after murdering his father Tywin. When Tyrion confronts Ellaria about her role in the death of his niece, Princess Myrcella, Ellaria attempts to justify herself and states that there are no innocent Lannisters. She then adds that her greatest regret was that Oberyn died fighting for Tyrion. When Daenerys the commands that Ellaria must respect Tyrion as her new Hand, they move on to discuss strategies. Daenerys and Tyrion agree with Yara's idea to attack King’s Landing immediately, and that the Unsullied army should attack the Lannister home of Casterly Rock while the Westerosi armies lay siege to the capital. Though reluctantly, Ellaria and Olenna both eventually acquiesce to Tyrion's plan to use the Martell and Tyrell forces to lay siege. Tyrion's plan involves using Yara's portion of her Iron Fleet to transport the Dornish and Tyrell forces across the Narrow Sea to the capital, allowing the xenophobic interpretation of foreign invaders to be depleted. When everyone has left, Daenerys requests a private audience with  Olenna, stating her awareness of the fact that Olenna is on her side due to their mutual hatred for Cersei, rather than a love for Daenerys herself. In response, Olenna encourages her to be “a dragon,” rather than a "sheep,” like the other high lords and ladies.

Some time later, out on the Narrow Sea, Yara and Theon Greyjoy sail with the Iron Fleet alongside their Dornish allies: Ellaria, Tyene, Obara and Nymeria. In their quarters, the Sand Snakes are lying in bed and argue about killing Lannisters. Elsewhere, Ellaria drinks Ironborn liquor with Yara and Theon, which she compares unfavorably to Dornish wine. Ellaria asks Yara if she had ever been to Dorne, to which Yara responds that she has been there a few times. Ellaria responds that there is a boy in every port in Dorne and Yara tells her, "A boy, a girl. Depends on the port." As they begin to flirt with one another, and Ellaria motions for Theon to get her more wine, Yara explains Theon is not a servant but will be both her advisor and protector once she has killed their uncle, Euron Greyjoy, who is now allied with Queen Cersei. Ellaria then invites Theon to have a threesome with her and Yara, but Yara tells Ellaria to leave him be. While Ellaria and Yara began kissing, the ship is suddenly struck. Racing to the deck above, Yara and Theon discover that their fleet has been ambushed by their uncle’s own Iron Fleet. Euron's flagship rams into Yara's ship and lands a boarding party, with their uncle at the forefront of the attack. Yara and her men, along with the Sand Snakes, fight fiercely but are overwhelmed by Euron's soldiers. Ellaria’s daughter Tyene retreats below decks to protect her mother on Yara's orders, while Obara and Nymeria fight against Euron's men. Obara then fights Euron, who quickly kills her by impaling her with her own spear. An enraged Nymeria then attacks him with her whip but Euron swiftly outmaneuvers her and strangles her to death with it. Though Tyene herself kills several of Euron’s men below deck, she and Ellaria are also overwhelmed and eventually taken captive. With the entire fleet burning, Euron finally captures Yara and then goads his nephew to come save his sister. Theon is about to come to Yara’s aid, but he instead panics when Euron's men begin mutilating the wounded sailors, reminding him of violent traumas he’s experienced in the past. To Yara's dismay, the triggered Theon quickly returns to a traumatized state and jumps overboard, abandoning his sister, while Euron laughs with cruel glee. Upon surfacing, Theon clings to floating driftwood, as Euron's fleet starts sailing towards King's Landing with the imprisoned Ellaria, Yara and Tyene. Theon watches helplessly as their entire armada is decimated in flames and his uncle’s ship disappears into the night.

Upon Euron Greyjoy’s return to King’s Landing, he parades Ellaria, Tyene and Yara through the streets of the capital, and the crowd take great delight in pelting them with insults and trash. As a token of his loyalty, Euron then throws Ellaria and Tyene in chains at the foot of the Iron Throne, occupied by Cersei herself. Ellaria spits hatefully at Cersei's feet, though she is clearly horrified at the sight of Ser Gregor Clegane looming over her, even more monstrous than when he killed Oberyn. As Euron stands next to the throne with the captive Sand women, Cersei proclaims Euron commander of her naval forces as well as assuring him of her hand in marriage once the war is won. A jealous Ser Jaime quietly mutters that the same people who cheered for Euron would do the same if Cersei put his head on a spike. Euron ignores the jab, but responds with one of his own by asking Jaime for advice on how to sexually please his sister. A furious Jaime almost lunges at Euron, but Euron gleefully insists on saving it for later.

Afterwards, Cersei confronts the bound and gagged Ellaria and Tyene in their cell. Accompanied by Ser Gregor and a former maester named Qyburn, Cersei recalls Oberyn's showdown with Clegane during her brother Tyrion's trial by combat. She sadistically recalls the savage murder of Oberyn to Ellaria and how Ellaria screamed at the sight of it. Cersei then provokes Ellaria's sorrow by inferring that Oberyn brought his death upon himself by taunting Clegane instead of just leaving him to die. She then mentions raising her daughter Myrcella, and the fact that Ellaria murdered her with poison. Cersei goes on to praise Tyene's beauty and suggesting that she is Ellaria's favorite child. She contemplates how she will execute them both, suggesting Ser Gregor kill them the way he killed Oberyn. However, opining that it would be too fast a death, she suddenly kisses Tyene on the lips with the same coated poison Ellaria had used on Myrcella, citing poetic justice. Cersei further torments Ellaria by having Qyburn confirm the uncertainty of when the girl will die, but also the inevitability of it, as the Long Farewell varies on how long it takes to kill, depending on the strength of its victim's constitution. Cersei then informs Ellaria that she will be left alive to witness the event and watch her daughter's "beautiful face crumble into bone and dust,” all the while forced to contemplate the acts she’s committed, even to the point of being force-fed if she tries to starve herself to death. Before leaving, Cersei orders for torches to be routinely replaced so that Ellaria doesn't miss a moment of Tyene's demise. A devastated Ellaria then frantically struggles against her chains in a futile effort to reach her dying daughter.

*In the aftermath of Ellaria’s imprisonment, follow Cersei's journey through the rest of the series.