Hell on Earth is a documentary about Ken Russell's 1971 film, The Devils. Film critic Mark Kermode chats to Russell as well as two of the film’s stars, Georgina Hale and Murray Melvin. Also included are scenes that were cut from the released film for being too controversial.

In 17th-century France, Father Urbain Grandier seeks to protect the city of Loudun from the corrupt establishment of Cardinal Richelieu. Hysteria occurs within the city when he is accused of witchcraft by a sexually repressed nun.