It's hard to summarize the plot of Slaughterhouse-Five neatly... because everything is going on at the same time. Since the main character, Billy Pilgrim, travels through time, we jump from 1944 to 1967 to Billy's childhood and back again. We're going to try to keep this summary at least somewhat chronological, but bear in mind that the only way you'll be able to get a sense of the crazy detours and switchbacks that characterize the novel is by reading it. (And, of course, you can also consult our chapter-by-chapter summary if you get confused along the way.)
Slaughterhouse-Five starts with the narrator. He never officially announces, "Hello, I am Kurt Vonnegut," but he is clearly speaking as Vonnegut. He talks about the difficulty he has trying to find ways to write about his experiences in Dresden during World War II, and he makes references both to teaching at the University of Iowa's famous writing program and studying anthropology at the University of Chicago—both of which Kurt Vonnegut did in real life. The narrator introduces us to the two people to whom the book is dedicated: Mary O'Hare and Gerhard Müller. For more on these two and their significance, check our "Characters" section.
After this autobiographical intro, we get to the book itself, which stars a fairly pathetic young man named Billy Pilgrim. Billy is in optometry school (optometrists are the guys who fit you with glasses if you have eye problems) in upstate New York in 1944 when he gets drafted into the army. He isn't even a fully trained soldier; his job is to be the chaplain's assistant, leading his regiment in hymns to keep their spirits up. Nevertheless, despite his complete lack of suitability for war, Billy is deployed to Luxembourg in December 1944 to fight the Germans in the Battle of the Bulge.
Once Billy gets to the battlefield, he becomes utterly confused; he isn't even carrying a gun. (Oops.) He is left walking through enemy territory like a lost lamb until he gets picked up by another American recruit, a crazy bully with a love of torture implements named Roland Weary. Weary becomes so angry at Billy's lack of interest in saving his own life that he threatens to shoot him. Just as Weary is aiming at Billy, a group of German soldiers take both men prisoner. Weary winds up dying on the trek from Luxembourg to a prisoner of war (POW) camp in Germany, blaming Billy for his capture all the while.
Billy arrives by train at a prison compound in the middle of a German death camp for Russian soldiers. The compound houses mainly British troops, who have all been prisoners since near the beginning of the war. These soldiers have been eating well and exercising for most of the war, so they're in great spirits—and they're pretty disgusted by the state of the American recruits, especially weak, clownish Billy Pilgrim. It's in the British compound that Billy meets Edgar Derby, a high school teacher who will be shot at the end of the war for looting, and Paul Lazzaro, a total psycho who promises to send an assassin to kill Billy after the war for letting Roland Weary die.
Billy and Edgar Derby are both sent to a POW center in Dresden, Germany, to wait out the war. This POW camp is located in an abandoned slaughterhouse (see "What's Up With the Title?" for why this matters). Soon after they arrive in Dresden (on February 13, 1945), American bomber units attack the city, setting fires that end up consuming pretty much all of Dresden. Thousands of people die. (For more on the Dresden firebombing, check out "In a Nutshell.") Billy and a small group of his POW comrades have to climb through the ruins of buildings and bodies to find water and shelter. It's Billy's job, as a prisoner of war, to help dig bodies out of the rubble of the city.
When Billy is finally freed, following the German surrender in May, 1945, he goes back to upstate New York and starts optometry school again. He gets engaged to Valencia, the daughter of the school's owner. Then, suddenly, he has a nervous breakdown and checks himself into a veteran's hospital to recover. Supposedly, he does get better—but after that, Billy will find himself suddenly crying, silently and without apparent reason.
Flash-forward about two decades and Billy has two children: a daughter, Barbara, and a son, Robert. Robert was kind of a wild kid as a teenager, but now he is a Marine fighting in Vietnam. Barbara—well, we'll get to her in a minute. Billy and Valencia have been (mostly) happily married for 20 years when everything goes wrong. Billy gets into an airplane with his father-in-law, Lionel. The plane crashes into the side of a mountain in Vermont and everyone except Billy is killed. Billy suffers an intense skull fracture. While Billy recovers in the hospital, Valencia dies of carbon monoxide poisoning in her car.
At the hospital, Billy rooms with an extremely energetic 70-year-old named Bertram Copeland Rumfoord, who is recuperating from a broken leg he got on a ski trip with his 23-year-old wife. Rumfoord is a historian who wants to write a book about the Air Force. He wants to include a blurb about Dresden, but he is frustrated because a lot of information about the raid is still classified.
Rumfoord does not see why the Air Force won't tell the world about such a fantastic, successful raid. He thinks it's because they are worried about the opinions of a bunch of bleeding hearts who might disapprove of the burning deaths of 135,000 non-combatants. Billy tells Rumfoord that he was at Dresden during the firebombing. Rumfoord wants to convince Billy that the raid was absolutely necessary, no matter how terrible it was to experience on the ground.
As Billy regains his ability to move around, he suddenly appears on a talk-radio show in New York talking about his experiences not as a POW—but as an alien abductee. He writes to the local paper in his hometown to tell the world about the people of the planet Tralfamadore. (We actually hear about Tralfamadore in the second chapter of the book, but, chronologically, this takes place quite late in Billy's life.) Billy's aliens are green and shaped like toilet plungers. Billy explains that they took him and a young actress named Montana Wildhack to be part of a zoo exhibition the year before. The Tralfamadorians, Billy tells the public, have a lot to teach us about time.
The Tralfamadorians see everything differently because their vision works in four dimensions. Thanks to this, they know that every moment in time is separate, eternal, and happening at the same time as every other moment. So when you see someone die, they may not be doing so well in that particular moment, but in all of the moments before then, they're still great. Death itself is an illusion, as is free will. Each point in time has always and will always be exactly the same. There is nothing we can do to change it, which, Billy thinks, should be a comfort to all of us.
Barbara, Billy's daughter, is incredibly embarrassed that he has announced all this in the newspaper, and insists on taking control of his life because he cannot care for himself anymore. It's probably not helping Billy's case for his own sanity that, during all of his arguments with Barbara and his experiences in the hospital, he keeps skipping in and out of time. His visits to Tralfamadore, his wartime captivity, and his life with his family all seem to be happening simultaneously.
See, Billy is really receptive to the Tralfamadorian way of looking at things, because he has been disconnected from time since 1944. He has seen his own birth and death many, many times, so he is uniquely qualified to believe that each independent moment is its own complete world. After all, this is both how Billy experiences time and how the novel is told—scene by scene in tiny chunks of narrative that only make sense when you look at them all at once.
The novel ends with Billy digging through the rubble of Dresden to find bodies for cremation. After finishing his job, he and his POW pals are sent to a stable to wait out the rest of the war. When the war in Europe ends, the stable door opens. Outside, all is silence except for the sounds of the birds singing, "Poo-tee-weet?"