Using his own terminology, Billy Pilgrim is “unstuck in time”, which means he is moving between different points in his life uncontrollably, although he is aware of it at certain of those points as witnessed by the letter to the editor he writes to the Ilium Daily News about his situation. Primarily, he is moving between three general time periods and locations. The first is his stint as a GI during WWII, when, as a pacifist, he was acting as a Chaplain’s assistant for his unit. This time is largely as a POW, where he was in Dresden the day of the bombing, spending it with among others an older compassionate GI named Edgar Derby, and a brash loudmouth GI named Paul Lazzaro. The second is his life as an optometrist in Ilium in upstate New York, eventually married to the wealthy and overbearing Valencia Merble, and having two offspring, Robert, who would spend his teen-aged years as a semi-delinquent, and Barbara, who would end up much like her mother.
The story is told in a non-linear order by an unreliable narrator (he begins the novel by telling the reader, “All of this happened, more or less”). Events become clear through flashbacks and descriptions of his time travel experiences. In the first chapter, the narrator describes his writing of the book, his experiences as a University of Chicago anthropology student and a Chicago City News Bureau correspondent, his research on the Children’s Crusade and the history of Dresden, and his visit to Cold War-era Europe with his wartime friend Bernard V. O’Hare. He then writes about Billy Pilgrim, an American man from the fictional town of Ilium, New York, who believes that he was held at one time in an alien zoo on a planet he calls Tralfamadore, and that he has experienced time travel.
Source: Slaughterhouse-Five (1972)