Ivan Denisovich Shukhov wakes up at five AM in a camp for political prisoners in Siberia. Today, he feels ill and lies in bed for a little longer. A mean guard, the Tartar, catches him there and sends him to the guardhouse, where he's forced to clean the floor but is not imprisoned. Shukhov next goes to the medical dispensary, where the medical assistant Vdovushkin tells him his temperature is too low to be kept back from work. Shukhov next rushes to the mess hall, where a prisoner named Fetiukov has saved his breakfast for him, and back to the barracks, to hide his bread ration in his mattress, before roll call.
Shukhov and the rest of the squad follow their leader Tiurin to roll call, where a prisoner named Tsezar shares a cigarette with him. The cruel Lieutenant Volkovoi orders the guards to search the prisoners for extra non-regulation underclothes. In Shukhov's 104th squad, Tsezar and Captain Buinovsky are found to have extra clothing. Buinovsky, who has only been in the camp for three months, tells Volkovoi he can't legally search them, and for that, Volkovoi sentences him to ten days in the cells. Finally, the column of prisoners sets off, flanked by guards with machine guns, to the work site. On the way, Shukhov thinks of writing to his wife. In her letters she has talked about how the men no longer work on the communal farm but instead make money painting carpets. That day, Shukhov's squad will be working at a half-completed power station. Shukhov eats the bread he has concealed in his coat and enjoys the time before work begins.
Tiurin assigns Shukhov and a prisoner named Kilgas to find something with which to cover the windows. Kilgas knows where there is some roofing felt, and he and Kilgas go and swipe it. Other men cut it to cover the windows, while Shukhov fixes a stovepipe with the help of a Ukrainian boy named Gopchik. The men notice the sun is above head in the sky and Buinovsky informs them that the Soviet government has decreed that the sun is at its highest at one rather than twelve o'clock. Shukhov thinks about how he came to be in prison: He was a POW who escaped from the Germans only to be charged with treason by the Russians when he returned to Soviet lines. Already, it's time for lunch, and the squad goes to the mess hall. Shukhov is able to swipe two extra bowls, which means that he'll get one of the extra bowls for himself. Pavlo lets Buinovsky have the extra bowl.
Shukhov brings a bowl of oatmeal to Tsezar in the camp office where he works. There, Tsezar and another prisoner are arguing about Eisenstein's films. On his way out, Shukhov finds a bit of hacksaw blade in the snow and pockets it. Back at the power station, Tiurin tells the story of his discharge from the military and attempts to evade capture while Shukhov smokes a cigarette with tobacco borrowed from two Estonians who are like brothers. Tiurin returns and they set to work. Shukhov, Tiurin, Senka, and Kilgas mortar the blocks of a wall in place, while Buinovsky and Fetiukov - and then Buinovsky and Alyosha, when Fetiukov becomes too lazy - bring the mortar up a ramp in barrows. Der, the building foreman, comes to up and threatens to turn Tiurin in for another prison term for stealing the roofing felt, but Tiurin insists it was already there. His men rise and stand with him against Der, who backs down. Shukhov is just getting into the swing of laying the blocks when the signal to end the work day sounds.
There is still a whole load of mortar left which will freeze overnight. Tiurin sends the other men away, and he, Kilgas, Senka, and Shukhov race to use it up. Kilgas, Senka, and Tiurin finally have to turn their tools in to the machine shop, but Shukhov swiped a nice light trowel long ago and finishes the wall by himself. Senka waits for him and the two rush through the crowd to the gate. The guards take a long time counting and recounting the prisoners because one man is missing. It turns out to be a Moldavian who fell asleep while plastering. After a long wait, the guards allow them to begin walking back toward camp. Part way there, they see a column of men from the machine works and race them back to camp. They don't want to wait behind the machine workers because the guards take a long time searching them for knives. Shukhov's column makes it back first and just as he's about to be frisked, he realizes he has the hacksaw blade in his pocket. He hides it in his mitten and keeps from being found out. Back in the camp, Priakhov, Volkovoi's lieutenant, charges the Moldavian with attempted escape and sends him to the cells for ten days.
Shukhov goes to wait in line at the parcels office for Tsezar, in case he has received a package. Tsezar comes to take his place in line and tells Shukhov he can have his serving at supper. Shukhov rushes to the mess hall and braves the wood club of the mess orderly to join his squad and get inside. He manages to get two thick bowls of soup for himself and sits enjoying them as he eats. He next goes to the Lett in Barracks 9 and buys two glasses of tobacco from him. Finally he goes back to his barracks, where he glances longingly at the contents of Tsezar's package and decides to save all his extra bread for tomorrow. Shukhov also conceals his bit of hacksaw blade in a partition, planning to sharpen it and use it to make money repairing shoes.
Buinovsky and Tsezar share his food package. A young guard, "Snubnose" enters and takes Buinovsky away to the cells for ten days. Ten days with little food, in cold cells, which Shukhov knows can permanently ruin a man's health. The men are called outside for the evening recount, and Shuhov tells Tsezar how to keep his food from getting swiped. Shukhov smokes a cigarette with his new tobacco during recount and rushes back inside to protect Tsezar's package. In return, Tsezar gives him two biscuits, some sugar, and a slice of sausage. He eats the sausage and gives one of his biscuits to Alyosha. Alyosha is reading his Bible and tries to convince Shukhov to find solace in religion, but he can't. He is just getting comfortable in his bunk when the men are called for a recount, this one taking place inside the barracks. Shukhov finally gets back in bed and thinks that this was an almost good day before he goes to sleep.