Eliezer Wiesel is a fourteen-year-old boy living in Sighet, Transylvania, at the start of World War II. He is very devout and wants to study Jewish mysticism. His father, who is a prominent leader of the Jewish community, thinks that he is too young. Nevertheless, Eliezer starts studying the cabbala with Moché the Beadle, a poor and humble man who works in the Hasidic temple. Moché teaches him that he must seek to ask God the right questions even though we will never understand the answers he gives us.
Despite ominous signs, the Jews in Sighet refuse to believe that the Fascists could ever do anything to hurt them. Moché is deported along with other non-Hungarians and taken to a concentration camp. He manages to escape and comes back to warn the townspeople of the atrocities that he has seen. They refuse to believe him, however, and think that he is either insane or just wants attention. People continue on in their normal, everyday lives through 1943. In 1944 the townspeople remain foolishly optimistic even after the Fascists come to power, Germany invades Hungary, and the German army itself arrives in Sighet. Eliezer's father refuses to try to escape the country. On Passover the persecution of the Jews begins. Jews are first forbidden from leaving their homes for three days, required to wear the yellow star, and then crowded into two ghettos. Even among the ghettos, people carry on as normal until one day when Eliezer's father is unexpectedly summoned to a meeting of the Jewish Council. He returns bearing bad news: all Jews will be deported. Eliezer goes to wake up the neighbors, and everyone begins to pack in preparation for the upcoming journey.
The first convoy of deported prisoners is kept standing in the middle of the hot courtyard, and Eliezer and others run to bring the parched individuals water. Eliezer's family is scheduled to leave in the last group, and they are moved into the smaller ghetto, where an old family servant named Martha offers to hide them in the country. The family refuses to be separated from one another, and they join the rest of the community in the synagogue to be deported. The next day, the prisoners are crowded into cattle wagons on a train.
Inside the train it is so crowded that people have to take turns sitting down. Young people openly copulate with each other, and the prisoners are forced to give up all their valuables. A woman named Madame Schaechter is on the train and begins to lose her mind, having earlier been separated from her husband and two older sons. She starts to scream hysterically about a flaming furnace she claims to see in the distance, and she scares the other occupants of the train. They try to silence her by beating and gagging her, but she nevertheless screams repeatedly throughout the night. Finally, when the train arrives at Birkenau/Auschwitz, the prisoners see the flaming chimney that Madame Schaechter had prophesied.
Upon arriving at Birkenau, Eliezer is separated from his mother and sister, but manages to stay close to his father. The prisoners then march past SS officer Dr. Mengele, who "selects" who will live and who will go to the crematory. Eliezer and his father are told they are going to the crematory and are filled with terror as they march closer and closer to a fiery pit. At the last minute, the line of men turns away from the flames. The prisoners are then forced to strip, run, bathe, and redress, all the while being pummeled by veteran prisoners and SS guards. Eliezer and his father are taken to the gypsies' camp, where they are harangued by an SS officer. The prisoners then march to Auschwitz.
At Auschwitz conditions are better and the fellow prisoners not as brutal. Finally, the prisoners are allowed to sleep. Eliezer refuses to eat his first ration, a plate of thick soup, but the day is much better, with people sitting and talking with each other in the sun. For several weeks the prisoners follow a tight schedule of meals, roll call, and bed. At the camp Eliezer and his father meet a distant relative, Stein of Antwerp, who is seeking news about his family. Eliezer lies to him, telling him that his family is well, and the man retains his will to live until he finds out the truth. The prisoners are then transferred to Buna.
At Buna Eliezer is placed in a good work unit, the musician's block. All he has to do is work in a warehouse counting electrical fittings. He meets a Polish violin player named Juliek and also befriends two Czech brothers named Yossi and Tibi. The foreman Franek gets Eliezer's father placed in the same block also. Eliezer is summoned to the dentist to get his gold crown removed, but he feigns illness twice and manages to keep it for awhile. However, Franek beats his Eliezer's father until Eliezer gives the crown to him in exchange for some extra food. One day the Kapo (head of the block) Idek flies into a violent rage and beats Eliezer. A young French girl passing as Aryan comforts him in German. Many years later, Eliezer meets this woman in Paris, and she confesses that she is Jewish and never spoke German in the concentration camp except to him.
Another day Eliezer accidentally walks in on Idek having sex with a young Polish girl. He laughs out loud, and Idek punishes him by having him publicly lashed twenty-five times. On a Sunday, an air-raid siren goes off, and the prisoners are locked down. They regain hope that Germany will soon be defeated. Two cauldrons of soup are accidentally left out, and one starving man crawls over to them and dies with his face in the soup.
The SS begins having public hangings during roll call. Eliezer is disturbed by the first execution, although the man condemned to death is calm and unafraid. Afterwards, all the prisoners are required to march past his hanging body. The only time that the prisoners weep at a hanging was when a young child, "a sad-eyed angel," is hanged for conspiring to blow up the electric power station. The entire group of prisoners cries, and a man standing behind Eliezer wonders out loud where God is.
Eliezer refuses to celebrate Rosh Hashanah and Yom Kippur. Though he does not doubt God's existence, he does question his justice, and he accuses him for the existence of concentration camps. Eliezer's father does not want to observe the religious holidays either, although most of the other prisoners do. The SS holds a selection for the crematories right after the new year. Dr. Mengele holds judgment once again, and Eliezer runs as fast as possible past him. He passes, but his father does not. Luckily, however, his father convinces the SS officers that he is still strong enough to live and escapes death. Akiba Drumer, formerly a devout religious mystic, loses his faith and his will to live, and he goes to the crematory.
During winter Eliezer's foot swells up from the cold, and he has to go to the hospital to get an operation. A bedmate warns him to escape the hospital before the next selection because all the invalids will be taken to the crematory. The doctor for Eliezer's operation is kindly, and although Eliezer panics that his leg has been amputated, tells him that he will be able to walk in a fortnight. Soon, however, the camp is to be evacuated because the Russian army is approaching. Eliezer and his father decide to be evacuated with the rest of the prisoners, instead of remaining behind in the hospital.
The prisoners are forced to run for more than forty-two miles without resting. Guards shoot those who fall behind, and others are trampled underfoot by the crowd behind them. When they are finally allowed to rest, Eliezer and his father have to keep each other from falling asleep and dying in the snow. A man named Rabbi Eliahou comes around looking for his son, who he was separated from during the run. Eliezer realizes that the man's son had purposely run away from his burdensome, weak father, and he prays to God for strength not to behave as callously towards his own father.
When they reach Gleiwitz, the prisoners are so crowded into barracks that people are piled on top of each other. Eliezer finds himself lying on top of Juliek, who has miraculously transported his violin all the way there. In the middle of the night, Juliek plays Beethoven soulfully on his violin for an audience of dead and dying men. After three days, there is another selection, and Eliezer creates a disturbance so that his father doesn't have to go to the crematory. The prisoners are then crammed into cattle wagons, a hundred per car.
Inside the car, men are dying, and Eliezer becomes indifferent to life and death. Eliezer's father looks almost dead, and Eliezer has to prevent him from being thrown out of the car when the train stops. The prisoners are not fed for ten days. Once, some German workmen throw pieces of bread into the car for entertainment, and the prisoners become murderous beasts trying to get at the food. One man even kills his own father for a piece of bread. Another time, someone randomly tries to strangle Eliezer, who is saved at the last minute by Meir Katz, who subsequently loses his will to live.
When they arrive at Buchenwald, Eliezer's father is too weak to go on and begs his son to let him sleep in the snow. After much argument, Eliezer goes to the barracks and falls asleep. The next morning he searches for his father but half hopes that he doesn't find him. He eventually finds him and spends much time taking care of him, giving him his own rations of coffee, soup, and bread. Knowing that he is about to die of dysentery, Eliezer's father tries to tell his son where the gold is buried. Eliezer's father is repeatedly attacked by his bunkmates and has his food stolen from him. The doctor refuses to examine him, and the head of the block advises Eliezer to eat his father's rations. When his father calls to Eliezer for water, an SS guard shatters his skull with a truncheon. His father does not die, but his body is removed the next day, January 29, 1945. Eliezer is ashamed that he is somewhat relieved to be free of him.
Eliezer remains at Buchenwald until April 11 and is transferred to the children's block. There is no more story to tell after his father dies. Right before liberation, there is much confusion in the camp. The Jews think that they will all be shot, but they are evacuated from the camp in thousands each day. On April 11, there is a battle between the camp resistance organization and the SS, with the resistance winning. That evening an American tank arrives at the camp.
After being freed, the prisoners think only of food. No one thinks of revenge. Eliezer becomes hospitalized for two weeks of food poisoning. When he recovers, he looks at himself in the mirror for the first time since he was in the ghetto. The eyes of a corpse look back at him.