The novel follows the story of American soldier, Billy Pilgrim. Billy is what is known in literature as an "unreliable narrator" - his experiences are written in a way that might make the reader think they are not exactly true. To reflect this, the novel is structured in a non linear fashion. This means events are not always written in the order that they happened. Billy's stories from the war are interrupted when he is taken by aliens (called Tralfamadorians) to live in a zoo on their home planet. He also becomes "unstuck in time" and experiences his life in a random order of flashbacks. 