Your Vice Is a Locked Room and Only I Have the Key (Italian: Il tuo vizio è una stanza chiusa e solo io ne ho la chiave) is a 1972 slasher film directed by Sergio Martino and starring Edwige Fenech, Luigi Pistilli, and Anita Strindberg.

It uses many elements from Edgar Allan Poe's 1843 short story "The Black Cat" and acknowledges this influence in the film's opening credits.

[1] The film's title derives from Martino's earlier The Strange Vice of Mrs. Wardh,[2][dead link‍] in which the titular character (played by Fenech) receives a note containing a similar phrase.

[citation needed] Oliviero Rouvigny, a washed-up, alcoholic writer, lives in an old villa in Teolo, where he abuses his wife Irina and their maid Brenda and hosts decadent parties for local hippies.

Fearful after being suspected for Fausta's death, Oliviero buries Brenda in the cellar and orders Irina to clean his mother's gown.

The next day, the Rouvignys collect Oliviero's visiting niece Floriana at a nearby train station, where a gray-haired man appears to spy on them.

The killer murders prostitute Giovanna, whose aunt kills the attacker, revealed to be Bartello, who was an escaped mental patient faking a new identity.

Irina chases Satan into the cellar where she discovers that Brenda's corpse has been uncovered, which convinces her that Oliviero intends to execute his plan.

She returns to the mansion to find Inspector Farla and a police officer; Mrs. Molinar had filed a complaint after Irina maimed Satan.