
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.

Responsible for five murders, Joshua Wade avoided justice for years and later confessed to killings that started from when he was just 14.

A man who terrorized Phoenix in an extensive year-long crime spree, committing nine murders with no apparent motive.

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.