Your Vice Is a Locked Room and Only I Have the Key (1972)

In the shadowy outskirts of Verona, a once-famed writer, Oliviero, is ensnared in the decaying web of his own existence. His life is a macabre puppet show, commanded by the phantom presence of his deceased mother. Morally bankrupt, Oliviero indulges in debauchery, hosting wild bacchanals for local hedonists, sharing his bed with his maiden and former protégé, and cruelly debasing his wife, Irina, before an audience of strangers. Terror is Irina's constant companion. When a young woman succumbs to a violent death, the finger of suspicion points to Oliviero. The plot thickens with the unanticipated arrival of Floriana, Oliviero's striking and audacious niece. As the estate's secrets unfold, a mysterious silver-haired stranger watches from the shadows. A sinister chain of female fatalities ensues, and dark fantasies of harming Irina breathe new life into Oliviero's barren creativity. Amid the suspense, the question looms - what is Floriana's true motive, and who is the silver-haired specter? In this tangled web of mystery, the only silent witness is Satan, a pitch-black feline with eyes that see all.

Your Vice Is a Locked Room and Only I Have the Key is a horror movie featuring Edwige Fenech and directed by Sergio Martino.

Your Vice Is a Locked Room and Only I Have the Key is currently streaming for free (ad-supported) on Tubi TV and it's also available on AMC+ Amazon Channel, Fandor Amazon Channel, Night Flight Plus and Screambox Amazon Channel.

It is also possible to buy Your Vice Is a Locked Room and Only I Have the Key on Apple TV.