In the midst of World War II, Sherlock Holmes rescues the Swiss inventor of a new bomb-sight from the Gestapo and brings him to England, where he quickly falls into the clutches of the evil Professor Moriarty.
It is prior to the commencement of World War II, and Japan's fiendish Black Dragon Society is hatching an evil plot with the Nazis. They instruct a brilliant scientist, Dr. Melcher, to travel to Japan on a secret mission. There he operates on six Japanese conspirators, transforming them to resemble six American leaders. The actual leaders are murdered and replaced with their likeness.
The police arrest a man climbing over the wall of a cemetery after midnight. He claims that he is being blackmailed and is following instructions he received by mail to leave $1000 on a certain grave. It turns out that he's not the only one who got a blackmail letter from the same person--calling himself "The Black Panther"--and it also turns out that all the recipients are connected to an opera company.
Topper is once again tormented by a fun-loving spirit. This time, it's Gail Richards, accidentally murdered while vacationing at the home of her wealthy friend, Ann Carrington, the intended victim. With Topper's help, Gail sets out to find her killer with the expected zany results.
In the middle of a pictorial lecture on his recent expedition to the Mongolian Desert, Dr. John Benton,the famous explorer, drinks from the water bottle on his lecture table, collapses and dies. His last words "Eternal Fire" are the only clue Chinese detective Jimmy Wong and Captain Street of the police department have to work on.
Dr. Bernard Adrian is a kindly scientist who seeks to cure a young woman's polio. He needs human spinal fluid to complete the formula for his experimental serum. Meanwhile, a vicious circus ape has broken out of its cage, and is terrorizing the townspeople. Can there be a connection?
Shipping magnate Cyrus Wentworth, downcast over a disaster to his ocean liner 'Wentworth Castle' (carrying, oddly enough, an illicit shipment of Chinese bonds) is shot in his office at the very moment of kicking out his daughter's fiance Dick Fleming. Of course, Captain Street arrests Dick, but reporter Bobbie Logan, the attractive thorn in Street's side, is so convinced he's wrong that she enlists the help of detective James Lee Wong to find the real killer.
When a police officer is murdered, Captain Street looks to Mr. Wong to catch the killer. Prime Suspect: Frank Belden Jr., whose father is a businessman well known for both his success and dishonesty. Mr. Wong faces increasing danger and is nearly executed himself as the investigation develops in treachery and complexity. As Mr. Wong follows the trail of dead bodies, he uncovers a jewel smuggling ring on the San Francisco waterfront and a case much larger than the death of a police officer.
A Scotland Yard inspector and his reporter friend arrive on vacation in a small village and are immediately involved in what is claimed to be a murder but the body has disappeared, leaving it to the inspector to find the body, determine the motive and find the killer.
When an escaped circus gorilla appears to have gone on a murderous rampage, a threatened attorney calls on the detective trio of Garrity, Harrigan and Mullivan to act as bodyguards. In short order, we discover that there is more to the attorney than meets the eye, and the ape may be innocent after all. When a pretty young heiress faces peril, it's up to our heroic trio to save the day.
Captain Drummond and his girlfriend want to marry but a hidden treasure in the house in which they want to celebrate their marriage is complicating the situation involving a series of deaths and an elusive murderer.
Detective James Lee Wong must find the "Eye of the Daughter of the Moon," a priceless but cursed sapphire stolen in China and smuggled to America. His search takes him into the heart of Chinatown and to the dreaded "House of Hate" to find the deadly gem before it can kill again.
On a train headed for England a group of travelers is delayed by an avalanche. Holed up in a hotel in a fictional European country, young Iris befriends elderly Miss Froy. When the train resumes, Iris suffers a bout of unconsciousness and wakes to find the old woman has disappeared. The other passengers ominously deny Miss Froy ever existed, so Iris begins to investigate with another traveler and, as the pair sleuth, romantic sparks fly.
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.