Timofey Berezin (Paddy Considine) works at a former top-secret, badly run and aged nuclear reprocessing facility plant in Skotoprigonyevsk-16, a former closed city and a naukograd. At the film's outset, he is exposed to radioactive contamination while selflessly trying to stop a Criticality accident malfunction. The facility's managers maintain his exposure was a survivable 100 Röntgen equivalent man, while accusing him of sabotage and suspending him without pay. Loyal coworkers, however, help Timofey discover the truth that he was exposed to 1,000 rems of radiation. Suffering from acute radiation poisoning, he has only days to live.