A boy from California goes to visit his grandfather in New Zealand, where he learns that the frail old man is a fanged flier by night.

A beautiful woman, Kate (Tina Grenville), is released from a sanatorium unaware that while she was away her husband John (George Lazenby) has begun an affair with her sister Marianne (Wendy Hughes). The two sisters live together in a creepy apartment block while John is away, and find themselves stalked by some mysterious strangers.

Naïve teenager Cedric Williamson, conspires with two misfits to photograph and blackmail adulterous couples. When the scam goes wrong they end up with blood on their hands.