Four young women travel to their college professor's new country home for a weekend getaway, only to discover that the house has a malevolent past.

A reporter witnesses a brutal murder and becomes entangled in a mystery involving a pair of Siamese twins who were separated at birth, one of them forced to live under the eye of a watchful, controlling psychiatrist.

After murdering his entire family, a man marries a widow with a teenage daughter in another town and prepares to do it all over again.