Charlie Chan at Monte Carlo

While attending a Monte Carlo art exhibit in which son Lee has a painting on display, Charlie meets a Monacan police inspector who knows Charlie by reputation. The highly impressed officer is very excited to meet the world famous detective and insists on comping him at the local casino. At the Chemin de Fer table Charlie witnesses the animosity between two rival financiers, Victor Karnoff and Paul Savarin, who are engaged in a feud of long standing. After Lee has lost all the house money he has been advanced by the inspector, the Chans are stranded on the way to the Nice airport when their taxi breaks down. While walking along the road, they come across the murdered body of Karnoff's courier, who had been carrying valuable bearer bonds for his employer. Charlie and Lee return to Monte Carlo, where they help the inspector solve the crime. Among the many suspects are Savarin, Evelyn Gray, a beautiful blonde without visible means of support, and Al Rogers, a shady bartender who is blackmailing Mrs. Karnoff.