Women are being tortured to death with various devices in the dungeon of an old castle by a mysterious, hooded figure who may be a notorious executioner from medieval times.

Professor James Anders is a seemingly mild-mannered teacher, an American working in Rio De Janeiro. Anders, bored with years of teaching, decides to put together a team to pull off a diamond heist during the Rio Carnival. Four international experts are brought together to carry out the robbery: a safe cracking expert, a master thief, a mechanical genius, and a playboy.

A young writer descends into madness. Alienated, neurotic, and plagued by guilt, Michele retreats from reality, loses interest in work, and comes to the brink of suicide before being sent to an asylum for shock therapy. Escaping from the asylum, Michele returns to his boyhood home, where he learns the reasons for his present mental state.