To many to name.
A wealthy, eccentric woman is dying of emphysema and has decided to leave all her money to her cats. Kassia (Gayle Hunnicutt), the woman's hairdresser, learns of this and hatches a plot to rob her before she dies and involves Wylie (Michael Sarrazin), the woman's estranged nephew. Unfortunately the one spoke in the wheel is that the aunts dozens of cats, as Wylie is terrified of cats. To appease him the aunt decides to get rid of the cats, having the younger nephew dump them far away. But obviously, given the name of the film, the cat's aren't going to take this lying down.
The film is a little slow to start, whilst it sets out the premise, but from Wylie's entry back in the house it ably builds suspense on a number of occasions, in this Hitchcockesque thriller with a twist.