The Shadow buys secret letters and uses them for blackmail. His fiendish deeds drives some of his victims to suicide or he turns to murder. The police have been after him for the last 12 months.
After his last murder, The Shadow left a clue behind. A police officer is killed by The Shadow before he can reveal his identity but the law knows that The Shadow is one of the numerous people in the house as he kills another to hide his identity, trying to get the clue back.
More cops arrive and surround the house. The key to the safe where the clue is hidden is stolen as the police close in on The Shadow. Telephone wires are cut and lights are turned off allowing The Shadow to escape detection. Shots are fired at the police. But a woman has recognised the clue and knows who The Shadow is. Will she live to tell his secret?
Granted some logic is lacking as, for example, whydid the Shadow linger around the house owned by a police officer, but it's a jolly fun show with heavy fog abounding, dodgy couples claiming they are siblings, an isolated mansion, a funny man who thinks he's a detective, and the shadow fleeting around the house taking pots shots at anyone who claim they know who the Shadow is. It's actually quite absorbing, and the actor who plays possible dim, posh accented Reggie is a scene stealer. He's an entertaining character.
