Genial shopkeeper Philip has to endure the constant nagging of a shrewish wife while he secretly yearns for a pretty young stenographer. When the henpecking gets to be too much, Philip murders his wife and manages to make her death look like an accident. A ruthless blackmailer and a low-key detective both discover Philip's secret, and he has to decide which of them poses the more dangerous threat.

Sherlock Holmes investigates when young women around London turn up murdered, each with a finger severed. Scotland Yard suspects a madman, but Holmes believes the killings to be part of a diabolical plot.