On the 20th anniversary of his death, the remaining relatives of Cyrus West (Wilfred Hyde-White) are called to his mansion to view the filmed reading of his will. Cyrus lets it be known how much he despised and loathed his kin by setting up a dogfight for the fortune and revealing that Annabelle West (Carol Lynley) is to be the sole beneficiary. However, to claim the inheritance, Annabelle must spend the night in the house with the rest of the family and be deemed sane the next morning.