What episode is River Monsters Chernobyl?

What episode is River Monsters Chernobyl? I reluctantly saunter in to be confronted with an episode of River Monsters called “Atomic Assassin,” in which Jeremy Wade goes to Chernobyl in search of giant mutant fish swimming in the cooling pond of the doomed reactor.

What season is River Monsters Chernobyl? Season 5 • Episode 1