It's a dark and stormy night ... what else in a horror movie ? ... when the owner of a sinister looking mansion or castle, Edmund Brandt (Ernest Milton)
has called his niece and only heir, Leonora Brandt (Barbara Shelley) to visit him alone. He's about to tell her about the family curse, the Brandt curse.
Since 700 years they have had a crave for raw meat, having a connection to a - or turning into a - Killer Cat (leopard or cheetah) ?
Against her uncle's wishes Leonora brings her slimy husband Richard (Jack May) and their 2 friends Allan (John Lee) and Cathy (Paddy Webster)
and it doesn't end well as a Killer Cat kills both Richard and her uncle. Richard cheated on Leonora with Cathy and Leonora now thinks she has
inherited the curse and that the cat kills on her command.

An old but cool postcard i found in a drawer

Now, Dr. Brian Marlowe (a wooden Robert Ayres) a psychiatrist and also the ex-boyfriend of Leonora takes her to a sanatorium in London, for rest
and snapping out of her delusions. He's sure that her delusions are caused by her husband's infidelities and his violent death by a roaming beast,
but Leonora is sure that the Leopard is there with her, in London, at the sanatorium, just outside her window and that her hands sometimes turns
into claws. Brian trusts her and even take her home to meet his sweet wife Dorothy (Kay Callard), Dorothy couldn't possibly be in any risk, could she ?

There's some clunky acting here and there but Barbara Shelley is great as Leonora and old Edmund Brandt's housekeeper Anna (Lily Kann) was fine
and the ending scenes on the streets in the London docklands were quite atmospherical and effective. But, hey, was it a Leopard or a Cheetah ?
The film is presented in 4:3, black & white, with an english mono audio. Extra: Original theatrical trailer, image gallery and a PDF with promo stuff