A bloody Caleb rises and Buffy finally kills him with the scythe by slicing him in two from the crotch up. Angel gives Buffy an amulet intended to be worn by someone ensouled, yet more than human. He tells her he will fight alongside her, but she turns him down, asking him to instead organize a second front in case she loses to The First. They discuss Spike, his soul, and Buffy's feelings for him. When Angel asks about the future, and if he has a place in it Buffy explains that she still needs to grow up. As he walks into the shadows, echoing his very first appearance, Buffy tells him there might be a future for them, but it will be a long time coming, if ever. He walks off after saying "I ain't getting any older."
Back at the house, Dawn angrily kicks Buffy in the shin for having Xander try to take her away from Sunnydale in the previous episode. Spike is in the basement, working out his anger on a punching bag with a crude drawing of Angel's face on it. He asks for the amulet, whose exchange he had witnessed from the shadows, and she explains that it is very powerful and meant only for a champion. She then hands it to him. Buffy tells Spike coyly that Faith still sleeps in her bedroom and she has nowhere to sleep. Spike says he doesn't want Buffy downstairs with him, because he still has his pride. When Buffy starts to walk upstairs, he says he doesn't have any pride at all when it comes to her and he says she can stay.
Late at night, as Buffy and Spike are sleeping in each other's arms, the First appears to taunt Buffy in the form of Caleb. His words give Buffy a plan; when Spike wakes up, Buffy tells him that she now knows that they will win.
The next morning, Buffy unveils her plan to the potentials off-camera. Afterward, Willow expresses to Kennedy her concerns about using magic again. She says this is the most powerful magic she will have attempted and asks Kennedy to kill her if it turns bad. Faith and Principal Wood also have a discussion while preparing the school for the battle. Wood demonstrates that he understands her defensiveness over getting emotionally involved with men and asks her to give him a chance after the battle. During the night, Buffy goes to the basement, where she apparently spends her last night with Spike.
The next morning, everyone arrives at Sunnydale High in a yellow school bus. The Potentials head to the seal in the basement while Kennedy helps Willow set up her spell in Principal Wood's office. After trying to give a farewell speech, Andrew is dragged off by Anya. Dawn leaves to set up her post with Xander, determined to see her sister again. Principal Wood leaves to wait at his post for Giles. The core four share a moment talking about going to the mall after saving the world which causes Giles to say "the earth is definitely doomed," echoing the end of the second episode of the first season of Buffy. Xander and Willow walk down the hallway with Buffy before each one peels off, leaving Buffy walking alone to the seal. The Potentials, Faith and Spike are waiting, and the potentials/slayers cut their hands to open the seal with their blood. They climb down the hole in the ground and come face to face with the army of Turok-Han. The Ubervamps spot Buffy, Faith and the Potentials, and attack. "Come on, Wil," Buffy pleads.
Willow sits in Principal Woods' office, the scythe before her. While chanting a spell, she places her hands upon the scythe, and both she and the scythe light up in an ethereal glow and her hair turns white, the opposite of Dark Willow. A flashback to Buffy's final speech to the Potentials reveals that Willow is channeling the essence of the scythe in order to activate Potentials all over the world. Defying the tradition of only one slayer per generation, Willow's spell will raise an army strong enough to do battle with The First. As Willow performs the actual magic, Kennedy tells Willow that she is a goddess. "And you're a Slayer," Willow replies. Kennedy takes the scythe to Buffy, who is deep in the fight with Faith and Spike against the army of the Turok-Han, numbering in the thousands.
As she pauses to give orders, Buffy is stabbed through her abdomen from behind by one of the Turok-Han and falls to the ground. She passes the scythe to Faith and asks her to hold the line. As she lies on the ground, she sees several Slayers fall, including Amanda. In the halls of the school, a few Turok-Han make it to the surface and attack the group guarding the entrances. A small group of Bringers also appear and attack. During the battle, Anya is bisected by a Bringer. Andrew fights until he is overwhelmed. Principal Wood is brutally stabbed by a Bringer who is then killed by Giles. Xander and Dawn take on some Turok-Han who are disintegrated by sunlight when Dawn throws open a skylight window, but more follow. In the Hellmouth, the First then appears to Buffy as a mortally wounded Buffy herself, saying "What more do you want?". Ordering The First to "get out of my face!" Buffy arises with renewed determination and knocks several Turok-Han off the ledge. Other Slayers are reinvigorated as well. Just then, Spike's amulet consumes him in blue light and blasts a hole upward into the sky. The sunlight is channeled through the amulet and in powerful rays that begin dusting the ubervamps. The ground begins to shake and rocks tumble. The few surviving Slayers start to flee. Buffy tells Spike to do so as well, but he insists on finishing it. They share a quiet moment as the world crumbles around them. With tears in her eyes, Buffy tells Spike she loves him, to which he replies, "No you don't. But thanks for saying it." He orders her to leave as he has to stay and finish the job. Buffy leaves and Spike, laughing and speaking to himself "I wanna see how it ends", disintegrates as the Hellmouth collapses.
On the way out of the school, the Slayers find Andrew crouched in a corner. Xander yells for Anya, whose dead and mangled body lies nearby. Dawn pulls him out. Faith is the last onto the bus and it pulls away, with Dawn looking through back for Buffy. Buffy, in the meantime, has climbed to the roof of the school and is running along rooftops trying to outrun the enlarging crater. She leaps onto the top of the bus. Watching as the bus speeds off out of town, the entire town collapses into itself, leaving a large crater as if from an underground nuclear bomb test.
The ground stops shaking. Everyone gets off the bus. Xander asks Andrew about Anya's death. He comforts Xander by telling him that Anya died saving him, to which Xander replies, seemingly soothed, "That's my girl. Always doing the stupid thing". Faith looks after a wounded Principal Wood. While Kennedy, Vi and a few others tend to the wounded newly made Slayers, everyone joins Buffy as they look at the large crater which was once Sunnydale. Giles asks how this could've happened, since everyone either died or is alive and with them. With sad eyes, Buffy answers with one word: "Spike". A silence follows, as everyone remembers their fight. Giles mentions that they should go to Cleveland as there's another Hellmouth there and lots more work to do. An exhausted Faith responds, "Can I push him in?". Dawn ponders, "What are we going to do now?" Buffy slowly begins to smile as she contemplates the future.