Vince has problems on the set of Smokejumpers. Ari meets up with a former colleague. ...

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

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

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

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

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