
World's Most Evil Killers delves straight into the stories of the world's most prolific killers. Each episode focuses on one notorious killer and features first-hand accounts of their behavior; such killers range from Fred and Rose West, Ed Gein, the Clown Killer, to the Milwaukee Cannibal. Accounts are also given by detectives who ran the cases, journalists who reported on them, relatives, experts on analysis, and sometimes even survivors.

Joachim Kroll murdered at least thirteen people during a span of over twenty years.

Volker Eckert was a German trucker whose murderous career lasted over 30 years; he strangled and killed as many as 19 women across Europe.

A look at the criminal profile of Marc Dutroux, a Belgian serial killer who was convicted for kidnapping, torturing, and sexually abusing six victims until getting arrested in 1996.

Fritz Honka killed four prostitutes in Hamburg during the early 70s.