The episode begins at sea. Stanis, and his fleet approach King's Landing. Davos' son Matthos thinks his god will protect them and when the fight is over his father will be the King's hand. Meanwhile, King's Landing Tyrion lies in bed with Shae, worrying that if the city falls, Stannis will burn every Lannister he can find. Shae promises not to let them hurt him. Meanwhile, Cersei waits for the attack with a glass of wine. Maester Luwin tries to work up to giving Cersei advice and then presents her with nightshade, just in case she feels like killing herself. She takes it but sends him away. Meanwhile, Bronn leads a drinking song with the goldcloaks and whores. He undresses one having a grand old time until the Hound comes in, very surly, and giving him the stink eye. They briefly debate the merits of killing.
The Hound says Bronn is just like him, only smaller. The Hound stares him down, saying Tyrion will miss him someday. Bronn faces him, ready to draw his dagger when the bells toll. Meanwhile Varys brings Tyrion the map he asked for with 50 miles of tunnels beneath the city. He's not planning on running. Varys warns Tyrion about Stannis using the dark arts and that he believes Tyrion is the only man who can stop him. At Sea Davos orders drums to respond to the King's Landing bells. In King's Landing, Joffrey wants Sansa to see him off to war by kissing his new sword, that he's named "Hearteater." Meanwhile, Sansa asks if he'll be out fighting with the vanguard. He explains that kings don't discuss strategy with stupid girls. She traps him by saying she is being stupid, of course he'll be out there, her brother Robb is always in the thick of things and he's "only a pretender."
Sansa's sure Joffrey will be back. "The worst ones always live," she tells Shae. Inside the castle walls, the guards prepare for war and families flee to safety. Meanwhile, Joffrey and Tyrion go to the wall and Joffrey is surprised to see his ships are gone. He demands answers, threatening to cut Tyrion in half if he doesn't get them. "That would make me the quarter man, and that just doesn't have the same ring to it," Tyrion replies. He grabs a torch and explains its all part of the plan. At Sea, Davos is concerned not to see any ships waiting for them. Meanwhile, Sansa and Shae hang out in a bunker for women. Cersei calls Sansa over and offers her wine. Cersei gets word of people stealing horses and orders them killed and their heads put on spikes. She asks for more wine. On the castle wall, they call for the archers as Stannis' ships approach. Joffrey whimpers when they wait to attack.
One ship comes out from King's Landing to meet Stannis' fleet. Meanwhile, Davos calls for archers and they watch as the ship sails silently past. They see there's no one on board. They see wildfire pouring out of the ship and Davos orders them to steer clear. From across the cliff, Bronn fires a single arrow into the water by the ships. Davos sees what's about to happen, but it's too late. Matthos ship ignites first, followed by Davos'. The people of King's Landing witness an incredible firework display as dozens of ships go up in the green flame of wildfire. Ships break into pieces and men scream in the water. Watching the display, Stannis orders his men forward. He says the dwarf has played his trick and it will only work once. One of his men warns him hundreds will die. "Thousands," Stannis corrects.
Meanwhile, drunken Cersei calls Sansa over to mock her for praying. She gets Sansa more wine and tells Sansa she should have been born a man, she hates being cooped up. Cersei says that if the city falls, she'll be forced to try to seduce Stannis. She counsels Sansa that her best weapon is between her legs, and then warns her that if the city falls, all of the women "should be in for a bit of a rape." Back on the wall, Tyrion orders his men to rain fire of Stannis' approaching fleet. He sends the Hound out to greet them. Joffrey looks generally panicked and twitchy. Meanwhile, Stannis' men land on the shore and flaming arrows rain down upon them from the castle. Still, Stannis and some men make it to the castle walls. The King's Landing guards throw rocks. Stannis orders his men to the mud gate. The Hound and his men emerge on the shore and fight, Lancel is wounded and retreats for the caste.
Drunken Cersei talks to Sansa about Jaime being taught to fight when they were children and her being sold to Robert for him to "ride like a horse." She goes to Shae and introduces herself then gives her lessons on curtsying. She can tell Shae isn't noble and wonders how she got where she is without learning how to curtsy properly. Lancel busts in and tells Cersei that Stannis fleet is destroyed but he still made land. Cersei orders him to bring Joffrey back to his chambers. Meanwhile, Cersei fesses up to Sansa that one of the guards isn't there to protect them; if Stannis takes the city, he won't be taking them alive. Back outside, the Hound splits men in two and keeps fighting. He's momentarily frozen in his tracks when a man on fire runs at him screaming. Bronn saves him with an arrow to the flaming man. The Hound is totally unsettled by all the fire and leads his men back in the castle walls. Meanwhile, Stannis orders the ladders up the walls and goes up one first. He's on the castle wall quickly.
Inside, the Hound calls for wine and chugs. Tyrion yells at him. The Hound tells him he lost half his men. Joffrey bleats at him to go back out. The Hound tells the city, the guard and Joffrey to eff off. He walks away. Meanwhile, Stannis' men use their ships as protection from the flaming arrows and approach the castle walls. They prepare a battering ram. Lancel comes for Joffrey to bring him back to the Red Keep. Joffrey asks if his mother had urgent business with him, looking for an out. Then he orders his men to represent him on the field of battle. Tyrion and all the men see him slink away. Later, Tyrion calls for his helmet and shouts that he'll lead the attack. The men need some convincing. Tyrion says there's another way out and he'll show it to them and they'll attack from behind.
He tells the soldiers not to fight for their king to money or anything, but to fight for their city, to protect their houses and their women. "Those are brave men knocking at our door, let's go kill them!" he shouts. The men rally. Not having seen any of this, Lancel reports to Cersei that the battle is lost and that Joffrey should go back out and fight. He tries to talk some sense into her, but she punches him in his arrow wound and storms off. Meanwhile, Sansa assures the women that Joffrey will save them and suggests they sing a hymn. Shae tells Sansa to go to her room and bar the door so the guard doesn't kill her. Shae's staying to say good-bye to someone and has a knife strapped to her leg. Back in her chamber, Sansa finds the Hound waiting. He tells her he's going someplace that isn't burning. "What about the king?" she asks. "He can die just fine on his own," he says. He offers to take her to Winterfell and promises to keep her safe.
When she says Stannis won't hurt her, he tells her he's a killer, as was her father and brothers. She realizes he won't hurt her. Meanwhile, Stannis and his men continue attacking the walls and Tyrion and his men sneak out behind them. Tyrion hacks away at soldiers' knees. They fight off the attacking group quickly and start chanting "Half man," but the victory doesn't last long when all new troops come around the corner. A new clash ensues. Tyrion is cut across the face, but his men protect him. Meanwhile, Cersei huddles with her young son Tommen on the Iron Throne and tells him the story of a mother and her cub and how she told him that one day everyone will bow to him. Outside on the battle shores, the troops keep fighting as a new group led by a rider on a white horse approaches. Cersei is about to feed Tommen the nightshade when troops bust in. She drops the bottle. On the wall, Stannis' men drag him away from the lost battle. Meanwhile, Twyin greets Cersei in the throne room. "The battle is over, we have won," he announces. The episode ends at this point.