Rich Cassie Denham (Sarah Padden) is a more than an eccentric millionairess. After her scheming relatives unsuccessfully try to have her committed to an institution, Aunt Cassie invites them for a weekend in the country to "study them like rats" and see to whom she will bequeath her fortune. At the stroke of midnight a murderer strikes, and in the suspense-filled hours just before dawn, her greedy, corrupt relatives are dispatched one by one. Having...