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

With untold millions at risk after the Chernobyl explosion, nuclear physicist Ulana Khomyuk makes a desperate attempt to reach Legasov and warn him about the threat of second explosion that could devastate the continent.

Lyudmilla ignores warnings about her firefighter husband's contamination; Legasov lays out a decontamination plan, complete with human risks.

Legasov and Shcherbina consider using lunar rovers to remove radioactive debris, while Khomyuk faces government hurdles in determining the truth about the cause of the explosion.

Legasov, Shcherbina and Khomyuk risk their lives and reputations to expose the truth about Chernobyl.