Charles Kessler (Bela Lugosi) is plagued by homicidal urges. His wife (Betty Compson), who had left him for another man, gets into a car accident that leaves her brain damaged and is kept in a cellar in secret, by Kessler's gardener. When an innocent man is executed for a murder Kessler committed in the house, his twin brother visits and tries to unravel the mystery. He discovers that Kessler is the killer and doesn't know it. His brother subdues him and contacts the police, who arrest Kessler.