After returning to Dresden with his wartime friend Bernard O’Hare, Vonnegut relates his unsuccessful attempts to write about his time as a prisoner of war.
The details of Billy Pilgrim’s life are explained, including how after his military service in Germany he marries, has children, and becomes an optometrist. Billy travels involuntarily through time, and after surviving a plane crash and his wife’s death, Billy’s daughter becomes worried about his sanity after he discusses his abduction by aliens. Billy describes his entry into the army and the first time he time-shifted.
Billy and his fellow soldier, Weary, are captured by Germans who take them to a house, where Billy falls asleep and wakes up in 1967, in the midst of giving an eye exam, and when he closes his eyes, he is transported back to war. He goes to 1967 and weeps on his bed, then is transported to Luxembourg with his fellow prisoners as they are taken to a railroad yard and Billy is separated from Weary.
On the night of Billy’s daughter’s wedding day, Billy cannot sleep as he knows that he will soon be kidnapped by the Tralfamadorians (aliens). Once abducted, Billy wakes up in a boxcar traveling across Germany. After people die on the train, including Weary, they arrive at a prison camp, and Billy time-travels back and forth until he’s back with the Tralfamadorians.
Trapped in a zoo enclosure by the Tralfamadorians, Billy travels back to the prison camp. Billy wakes to find himself in a psychiatric hospital, as he found his life meaningless after the war. He is introduced to the writer Kilgore Trout, and Billy time-travels back to the zoo. He is then transported to his wedding night, when he wanders back to the hospital bed in the prison camp and points out that one of the sick soldiers is a man named Kurt Vonnegut. Billy returns to Tralfamadore and learns that an actress, Montana Wildhack, has been brought in as his mate.
Billy time-travels to the day of his death, where he delivers a speech in a stadium and is killed by an assassin. Back in Dresden, the American prisoners are marched to the slaughterhouse that will serve as their quarters.
After Billy survives a plane crash, he is left unconscious for days, during which time he time-travels back to Dresden.
In Dresden, everyone is taken into a shelter in a meat locker, and Billy time-travels to a conversation with his daughter, who blames Kilgore Trout for Billy’s pronouncements of Tralfamadore. Billy recalls his first meeting with Trout and how shocked Trout was that Billy read his books. Billy invited Trout to his wedding anniversary party where a barbershop quartet sang a song that moved Billy. When Billy laid down, trying to figure out why the group had such an effect on him, he remembered the night that Dresden was destroyed.
While Billy is time-traveling, he is oblivious to his wife’s fatal car crash. He travels back to Dresden, two days before the end of the war, where he cries his first tears. After his daughter takes him home from the hospital, Billy drives to New York to tell the world about Tralfamadore. He gets on a talk-show and speaks about the nature of time, then later travels to Tralfamadore, where Montana feeds their child.
In Dresden, Billy, Vonnegut, and O’Hare are put to work excavating the ruins, where they discover the bodies of the dead. As the war ends and spring comes, Billy hears a bird ask him a question.