Plant workers and firefighters put their lives on the line to control a catastrophic April 1986 explosion at a Soviet nuclear power plant.

With untold millions at risk, Ulana makes a desperate attempt to reach Valery and warn him about the threat of a second explosion.

Valery creates a detailed plan to decontaminate Chernobyl; Lyudmilla ignores warnings about her firefighter husband's contamination.

Valery and Boris attempt to find solutions to removing the radioactive debris; Ulana attempts to find out the cause of the explosion.

Valery, Boris and Ulana risk their lives and reputations to expose the truth about Chernobyl.