Deep within the underbelly of Paris, there is a club which is the home of a secret, wicked society. At first it resembles an ordinary fetish or Goth nightclub, but within the cavernous building are many hidden rooms, one of which is known as "The Room of Souls," a private gathering place of the world's richest and most evil people. Their host is the elegant yet frightening Madame Sabatier. For their amusement each member takes a turn and spins a true tale of depravity.

Cannibal is based on the true-crime story of Armin Meiwes, the "Rotenburg Cannibal" who posted an online ad searching for someone to volunteer to be mutilated and eaten. Unlikely as it may seem, someone actually replied. The film shows a fictional portrayal of the meeting between the cannibal and his victim/participant, their homosexual relationship, and the eventual mutilation and murder of said victim.