Philo is in Vienna working for the US Government to see if Archer Coe is selling aircraft designs to foreign powers. He grabs the plans with Archer's signature, but is captured by police before he can escape. Deported he comes back to America and plans to confront Archer, but Archer is found dead in his locked bedroom with a gun in his hand. While it looks like a suicide, Vance knows better and the coroner finds that Archer has been shot, hit with a blunt instrument and stabbed - making suicide unlikely. But Vance is on the case and is looking to see if government secrets have been sold and who has murdered Coe. This is a remake of "The Kennel Murder Case" using aircraft designs and espionage instead of Chinese porcelain and dog shows.
Carmelita Fuentes is a fiery-Latin singer/dancer in Mexico City who has designs on Dennis Lindsay, an American publicity agent, for unclear reasons, while Lindsay's shiftless uncle Matthew Lindsay aids and abets her every step of the way to the marriage altar.
Knowing that is contains valuable helium gas, a gang of bad guys first tries to purchase the ranch which Gene straw-bosses. When that fails, they lay a hidden pipeline to snag the gas.
A notorious counterfeiter passes himself off as a Secret Service agent to Steve and gets him to unwittingly help him bilk the racetrack out of tens of thousands.
Choreographer Bob Connolly and prolific screenwriter Crane Wilbur teamed up on the direction of Warner Bros.' The Patient in Room 18. Patric Knowles delivers a delightfully comic performance as Lance, an outwardly normal young man obsessed with detective stories. When his obsession threatens to lapse over into lunacy, Lance is sent to the hospital for a nice long rest. It isn't long before he gets mixed up in a genuine murder mystery, using his second-hand knowhow to solve the case. Up-and-coming Ann Sheridan is quite amusing as Lance's nurse and confidante, while the murderer is played by a fellow who is usually cast as the murder victim.
Although Charlie and Lee are in Monaco for an art exhibit, they become caught up in a feud between rival financiers which involves the Chan's in a web of blackmail and murder.