A flu-stricken Buffy, reluctant to stay at home, patrols the cemetery. Xander, Willow, and Cordelia surprise her and she nearly stakes Xander. They try to convince her to go home, but the damage that Angelus has done so far continues to fuel her fire. Angelus appears behind her and attacks Cordelia. Buffy and Angelus fight until Angelus pins Buffy down. Willow throws a burlap sack over his head and he is scared off by crosses that they all carry. Buffy faints and the gang rushes her to the hospital. After being stabilized, she is admitted to the hospital for a few days against her will. Her mother reveals that Buffy has always hated hospitals ever since her cousin died in one while Buffy was there with her.
Joyce brings up the topic of Ms. Calendar's death to Giles and unknowingly brings up a topic Giles would much rather forget. Meanwhile, Xander, Willow and Cordelia wait to protect a very sick Buffy from the harm of Angelus. That night, Buffy has a dream where she sees a strange man follow after a kid. As she follows the man down the hall, flashbacks of her cousin's time spent in the hospital bring nightmares to mind. She awakes suddenly in the middle of the night and takes a walk down the hall. Two men exit the children's ward with a child that died that night. At the door, she overhears a conversation between Dr. Backer and Dr. Wilkinson about the doctors' experimental treatments on the kids. As she begins to leave, she encounters two children that tell her about "Death" and how he comes at night.
That night, Angelus comes to visit Buffy, but Xander stands guard. They stand face to face and exchange many harsh words until Angelus finally leaves, discouraged by the fact that he may not make it to Buffy's room with all the security. The next morning, Buffy's friends visit bearing gifts... all but Cordelia, that is. They all take a walk and Buffy tells them all about the conversation she overheard. The doctor was trying experimental treatments on the kids in the children's ward that Dr. Wilkinson didn't exactly agree with. Since forced to stay at the hospital, she plans to find out what the doctor is up to and Xander volunteers everyone's help. Cordelia and Xander sneak into the hospital's record room and search for records on the girl that died that night. Meanwhile, Giles and Willow search for information at the school library. While looking through the records, Cordelia is caught by the security guard. She flirts with him as a distraction so Xander can escape with the records. Once outside, Xander expresses jealousy about the flirting, while Cordelia retorts with jealousy about Xander's loyalty to Buffy.
Buffy takes a walk and finds the little boy. He is drawing a picture of the man she saw in her dream. Willow digs up information on Dr. Backer at the library with Giles. She finds that he has a large past of experimental treatments and investigations into his practices. Meanwhile, Dr. Backer is working on trying to cure the children's illnesses. After finding a solution that he thinks will work, he takes it to the children's ward to try it out. Before he can do anything, the evil creature attacks him and slashes him up. Buffy tries to stop him, but is thrown aside.
The next morning, Buffy informs everyone that Dr. Backer is not the suspect and shows them the drawing that Ryan drew of the creature. Xander, Giles, and Cordelia leave her alone and come up with a plan. Giles and Cordelia head back to the library while Xander stands guard against the threat of Angelus. At the library, Cordelia annoys Giles with constant questions. Finally, she finds a picture of the monster on the cover of a book and they research it. After searching, they find that it is called Der Kindestod. After Cordelia squeamishly describes what is going on, Giles takes over and then tells Buffy about how it sucks the life out of a child. Buffy flashes back to her time at the hospital as a child again. She sees her cousin freaking out while she helplessly watches. Buffy goes silent over the phone and then after several minutes, Willow takes it from her and hangs up. Buffy then realizes that Der Kindestod was the killer of her cousin.
The two head to Dr. Backer's office in search of answers. They find out that Dr. Backer was giving the children injections of the disease they already have in order to inoculate them against it. Buffy realizes that only sick people can see the demon, so she decides to infect herself with the vials of disease the doctor was using on the children. Willow stops her, warning her that the vials are 100% pure and would kill Buffy instantly if she drinks them. Willow then dilutes the disease in some water so Buffy can drink it "safely". Buffy's fever rushes to a near 107 degrees as she stumbles to the children's ward. She finds all the children are gone. They have headed down to the basement in hopes of escaping from Der Kindestod. After a few moments, Buffy sees Der Kindestod in the room and watches as he heads down to the basement. The door is locked, so Buffy and Willow rush to find access to the basement. Dr. Wilkinson tries to stop them, but Buffy shoves her aside. When security guards stop the two, Willow takes on the blame as Buffy makes her escape.
Buffy works her way to Xander and he helps her down to the basement. The children wait quietly in hopes of not being found, but then Der Kindestod picks up Ryan. He screams along with all the other children. Buffy arrives just in time and fights off Der Kindestod. Just as he is about to kill her, she snaps his neck and she leaves, leaning on Xander. Buffy finishes her rehabilitation at home with her friends. Her mother reluctantly waits on them all. Joyce then hands Buffy a letter from Ryan, which is revealed to be a drawing of her hailing over a dead Der Kindestod.