Charlie Chan at the Olympics

A concealed stowaway hijacks the Hopkins plane during a demonstration of remote radio control. The invention is stolen and the test pilot is murdered. Charlie Chan and his son begin to investigate the incident and connect it to a larger conspiracy.

Chan and his second son identify the stowaway, but they find only the man's body afterwards. The disappearance of the device deepens the mystery surrounding who stole it and why. The investigation shifts from the air to the passengers and their plans.

On the passenger list leaving Honolulu for the mainland are Richard Masters and Yvonne Roland. Masters, originally the intended test pilot, is sidelined by a shoulder injury and heads for the Olympics on a Pan Am Clipper. Roland travels toward Europe as part of the same journey.

German arms dealer Arthur Hughes is spotted among the suspects tied to the device. Chan and others begin to suspect a broader plot involving international interests. The implication is that someone intends to profit from the invention at the Olympics.

Several suspects head for Germany on the SS Manhattan, while Chan, Hughes, and Cartwright arrive ahead of them by taking the Zeppelin Hindenburg. The trio’s speed puts them on a collision course with those pursuing the device. The voyage sets the stage for a Berlin confrontation.

On the Manhattan, Lee Chan suspects Yvonne Roland as an adventuress. He sees her slip a note into her book and notices Hughes taking it. He confides his suspicions to Betty Adams, an Olympian acquaintance.

On the train toward Berlin, Lee sees Roland borrow a camera from Adams and overhears their talk about the device. Hughes warns Chan to drop the investigation after spotting a gun barrel in a passing car, pushing them to safety. Later, Hughes arranges for Adams' camera to be stolen, but nothing of value is found inside.

A hotel maid tries to steal the invention hidden in Adams' candy box, but Chan and Inspector Strasser foil the attempt. The maid rushes to warn her accomplices, while Chan secretly substitutes a harmless book for the device. The substitution goes unnoticed in the ensuing scramble.

Roland takes the candy box to her employer, the diplomat Zaraka. When they discover the substitution, Zaraka sends Chan a ticket to the Olympic opening ceremony. The political intrigue tightens as the race to control the device nears its climax.

Lee is kidnapped during the escalating device crisis. Chan agrees to go to Zaraka to exchange the device for his son, risking his own safety to save Lee. The stakes escalate as the opening ceremony approaches.

Hopkins is brought in to verify the device and confirms it as the real invention even though the ‘device’ presented is an imitation containing a radio beacon. The real device is implied to be hidden elsewhere, heightening the tension. The verification sets up the final confrontation.

Hughes and his men burst in, threatening to kill Lee unless the real device is produced. The police arrive in time to rescue Chan and subdue Hughes. Chan then reveals that Cartwright was responsible for the Honolulu murder and the accomplice’s shooting, exposing his criminal conspiracy.

With the conspirators brought to heel, Lee Chan secures victory in the 100-meter dash, providing a satisfying end to the Olympic quest. The investigation into the device’s theft is resolved as the truth comes to light. The family unity and Chan’s detective work are celebrated along with the Olympic triumph.