In June of 1941, fifteen-year-old Lina Vilkas is arrested by the Soviet Secret Police, the NKVD, from her home in Kaunas, Lithuania. She is arrested alongside her mother, Elena, and ten-year-old brother Jonas. Her father Kostas has been arrested earlier, and they don’t know where he is.
The family is given very little time to pack before they are loaded onto a bus full of other arrested civilians. They are then placed onto trains, where they remain in squalor with very little food for six weeks. Among them are schoolteachers, librarians, stamp collectors, and even a young mother and her newborn child. Lina meets a boy her age on the train named Andrius, with whom she initially has a rocky relationship, though over time they develop feelings for each other. Lina and Jonas find Kostas in another train car, and he encourages them to have strength despite their struggles.
They are then separated, and Lina, Jonas, and Elena, along with the rest of their train car, end up in Siberia, where the NKVD attempt to sell them to local villagers as slaves. They are not bought, and are instead brought to a collective Communist labor camp, where they are forced to do backbreaking work while subsisting on only three hundred grams of bread a day. The Vilkases are forced to live in a shack with an Altaian woman named Ulyushka, who is rude and demands rent. Lina is a talented and avid artist, and draws the things she sees every day in the hopes that they will one day make their way to Kostas, so that the family can be reunited once more.
In the camp, the NKVD continue to torture the deportees. Mrs. Arvydas, Andrius’ mother, is forced to sleep with the guards in exchange for her and Andrius’ life. Jonas almost dies from scurvy, and Andrius saves him by stealing a can of tomatoes from the NKVD officers. The NKVD try to force the deportees to sign a document sentencing them to twenty-five years of hard labor for their crimes against the state, but many of the deportees resist. Lina and her family are among them, and they are often punished for their resistance.
After several months in the camps, a list is drawn up with the names of deportees to be moved to another location. The Vilkases are on the list, but Andrius and his mother are not. Having expressed their mutual feelings for each other, the Lina and Andrius are sad, but promise to find each other in the future. Lina and the other relocated deportees are put on trucks, and then barges, and after several weeks they arrive in Trofimovsk, in the Arctic Circle, very close to the North Pole. The conditions here are even bleaker than in the previous camp, and the deportees are essentially left to fend for themselves in the wilderness while the NKVD live in relative luxury. The polar night sets in—180 days of darkness—and snowstorms begin in September. People die from the harsh conditions. Lina learns that her family was deported because her parents helped her cousin Joana’s family repatriate to Germany. Elena learns from a cruel officer that Kostas has died in prison, and Elena soon becomes sick and dies. Lina is left to take care of herself and Jonas alone. Jonas and other children begin to succumb to scurvy again. Miraculously, a doctor from the Soviet tribunal comes to the camp just in time, and brings medicine and supplies, saving their lives. Lina’s story ends when she sees sunlight on the horizon, and she knows they have successfully survived the winter despite the best efforts of the NKVD to have them perish.
In an epilogue, construction workers in Kaunas in 1995 find letters and drawings Lina has buried in 1954. She married Andrius, and buried the documents so that people would eventually learn of the Baltic genocide, long hidden by the Soviet Union. It is her hope that her story helps to ensure no such tragedy ever happens again.