Disaster lies over Castle Darkwood. While the castle owner is still fighting his imminent death, the family is already fighting over his heir. Shortly before his death, he changes his will to the benefit of his daughter, who should continue the girls school in the Castle, and his granddaughter Gwendolin, who shall inherit the entire fortune. Both sons go out empty. Thereupon ill-fated things happen: the girls disappear, a shrouded monk shape spooks through the dark park, people are found strangled to death by a whip: This is a case for Scotland Yard's finest! Inspector Bratt comes to solve the mysterious happenings...