The second and final Grand National Pictures film to feature The Shadow, played again by Rod La Rocque. In this version, Lamont Cranston is an amateur detective and host of a radio show with his assistant Phoebe (not Margo) Lane. Cabbie Moe Shrevnitz and Commissioner Weston also appear.
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.
An eccentric millionaire, unable to locate his only granddaughter, decides to divide his estate among a group of people less close to him: his niece and nephew, his attorney, his doctor, and his housekeeper. But complications and murder arise when two different women turn up, claiming to be the granddaughter.
In a cheap hotel-room in New York City Jelke shoots gangster Joe Wells, takes a package from his pocket and flees.Wells staggers into an alley. On her way to her apartment above a wax museum, Sue Gallagher, a reporter for the Chronicle, finds Wells' body and hides his corpse among the wax-figures in the museum and calls her paper to send a photographer so she can get a scoop on the killing of Wells, who had a $5,000 reward for his capture, dead or alive. Meanwhile, Henry Miggs, the museum owner find the body and is ready to call the police but his handyman, Clutch Tracy tells him to conceal it and avoid suspicion. From this point on it is a game of where-is-the-body....and the stolen South American diamonds Wells was carrying.
The Phantom Robber gets a fortune in jewels and some valuable papers from a robbery on the crack train "The Midnight Limited" and Val Lennon and his pretty assistant, Joan Marshall, are on his trail. But the Phantom strikes three more times and adds murder to his list. Val decides to use himself as bait, although Chief Harrigan and Joan beg him not to risk his life. But Val, disguised as a wealthy Canadian, boards the train for a rendezvous with a killer.
In this detective story, a super sleuth is hired by an insurance company to find a stolen emerald belonging to a rich man's daughter. He soon discovers that the theft was a hoax precipitated by the girl's boyfriend, an aspiring novelist doing research for his forthcoming novel. Real trouble ensues when the gem really is taken. Again the detective begins investigating. He soon discovers that the crook is an official at the insurance company.