Charlie Chan takes his wife and twelve children on an outing to a circus after receiving a free pass from one of the owners, Joe Kinney.

However, when Chan goes to meet him during the night's performance, he finds the man dead, seemingly killed by a rampaging gorilla who somehow escaped from his cage.

Macy finds a marriage certificate inside, showing that Kinney supposedly married circus wardrobe lady Nellie Farrell in Mexico.

Chan asks everyone to keep quiet and clear the area, so as not to cause a potentially fatal distraction for the medical staff during the delicate operation.

Meanwhile, Chan has noticed a newspaper article about a crime committed at a casino on the day of Kinney's alleged marriage.

Writing for The Spectator in 1936, Graham Greene gave the film a good review claiming that "Charlie Chan […] needs no recommendation".