Lamont Cranston assumes his secret identity as "The Shadow", to break up an attempted robbery at an attorney's office. When the police search the scene, Cranston must assume the identity of the attorney. Before he can leave, a phone call summons the attorney to the home of Delthern, a wealthy client, who wants a new will drawn up. As Cranston meets with him, Delthern is suddenly shot, and Cranston is quickly caught up in a new mystery.

Based on the 1930s comic strip, The Shadow is put up against his archenemy Shiwan Khan, who plans to take over the world by holding a city to ransom using an atom bomb. Using his powers of invisibility and "the power to cloud men's minds", The Shadow comes blazing to the rescue with explosive results.

The Shadow battles a villain known as The Black Tiger, who has the power to make himself invisible and is trying to take over the world with his death ray.