The Beast Must Die

Millionaire Tom Newcliffe invites a group of people to his rural English mansion, where he reveals that one of them is a werewolf and therefore must be killed. The group is composed of disgraced diplomat Arthur Bennington; Jan and Davina Gilmore, a pianist and his ex-student, now his wife; Paul Foote, an artist recently released from prison; and Professor Lundgren, an archaeologist and a lycanthropy enthusiast. They undergo various tests to detect whether they might be a werewolf, but the entire house is under surveillance, and the only way to determine the identity of the werewolf is for a certain combination of elements to occur all at once, including a full moon and the presence of wolfsbane pollen in the air. When the werewolf appears, it kills several guests, and Tom becomes obsessed in his hunt, suspecting Paul Foote.