Night is a memoir of a Jewish teenager named Eliezer, who, at the beginning of the story, is residing in a small town, Sighet, in Hungarian Transylvania. 

Eliezer studies the Torah, the first five books of the Old Testament, and a doctrine of Jewish mysticism known as the Cabbala. But his studies are interrupted when his tutor, Moshe the Beadle, is deported.

Moshe, however, returns after a few months to tell a horrendous tale. The German secret police force, the Gestapo, bundled everyone on board the train to a nearby forest and selectively butchered them. Moshe’s story finds no reception in Sighet, where everyone thinks he has lost his senses. 

By the end of spring in 1944, the Nazis occupy Hungary. Soon, repressive measures follow and the Jews residing in Sighet are crammed into ghettos. They are loaded onto a train and sent to Birkenau, a place that marks the entry into Auschwitz. When they arrive, they are in a state of extreme exhaustion and starvation. 

The males of the family, Eliezer and his father, are segregated from the females — mother and sisters — and they never get to see each other again.

Eliezer describes many "selections" of Jews in his memoir, the first of which is the evaluation and separation of those who can be put to work versus those who need to be killed straightaway. Eliezer and his father clear the first selection process. They are on their way to the prisoners’ barracks when they witness truckloads of Jewish babies being pushed into a furnace.

The prisoners are treated inhumanely, even as they are robbed of their clothes, tonsured, and sterilized with disinfectant before entering the concentration camp. From Birkenau, they are led to Auschwitz on foot. Eliezer arrives in a work camp, Buna, where he is assigned to an electrical-fittings factory. 

Due to extreme slavery and physical labor, the Jews suffer from malnourishment, and repeated "selections" leave them distraught. In the beginning, the Jews develop a sense of bonding and caring for each other. They are united by their religion and find peace in Zionism, the cherished idea of a Jewish state, Palestine, which Jews imagine as their holy land. 

The Jews face physical torture and endless humiliation in the camp. Eliezer becomes a victim of a brute foreman, who mercilessly extracts a gold tooth from his mouth with an old spoon.

To instill fear in the prisoners, they are made to witness the hangings of their fellow prisoners in the camp courtyard. To quell insubordination in the work camp, the German secret police force hangs a child related to the rebellion. The inhumane conditions and the looming fear of death in the camp induce cruelty among the inmates. Soon, their only concern becomes survival of the self. Human as well as familial bonds begin to crumble in the face of the atrocities. Sons become indifferent and abusive to their fathers. Eliezer too cannot remain untouched by it; he too loses his faith in people around him and in God. 

After Eliezer is in the camp for a few months, he undergoes a surgery to treat a foot injury. He is still recuperating in the infirmary when the Nazis decide to shift the camp due to advancing Russian forces. They fear that the Russians might liberate the work camp in the coming days. As a result, the prisoners are ordered to march fifty miles in a raging snowstorm to the Gleiwitz concentration camp. The extreme weather and intense exhaustion lead to the death of many prisoners. Upon reaching Gleiwitz, the prisoners are once again packed off into cattle cars. Another fatal journey begins: one hundred Jews board the train, but only a dozen come off it alive when the train arrives at the Buchenwald concentration camp.

Eliezer and his father’s mutual support help the duo survive the deadly journey. But in Buchenwald, his father gives up his fight against physical abuse and succumbs to a bout of dysentery. Eliezer is barely alive, his soul completely battered. Finally, the camp is liberated by the American army on April 11, 1945.