Billy Pilgrim is a war veteran and optometrist who has been traumatized by the events he experienced and witnessed as a prisoner of war during World War II. His trauma is so great he experiences and reexperiences events from his life out of order, in a way that magnifies his suffering. The wealth he has accumulated brings him no peace, and he is unable to connect with his wife and children, or anyone else, in any meaningful sense. His only happy moments seem to come from his interactions on the planet Tralfamadore, likely a fantasy he has created to cope with his trauma.
The narrator, presumably Kurt Vonnegut himself, describes his difficulty in organizing his thoughts about his own experiences as a prisoner of war during World War II and the challenges of writing about these experiences. These reflections make up the first chapter of the novel, where he mentions events that will be referenced as he tells Billy Pilgrim's story, demonstrating how this character is designed to reflect the negative impact of war on his own life. The narrator is largely absent from the narrative after the first chapter, appearing only for brief moments of self-reference.