While visiting the office of the Chief of Police Romaine (C. Henry Gordon), who is away on business, word is received that Petroff (Douglass Dumbrille), a well-known millionaire, has been murdered.

Romaine's bumbling godson, Police Inspector Marcel Spivak (Harold Huber) has been left in charge during the chief's absence, and is terrified of handling such a high-profile murder investigation.

Spivak suspects his butler, Antoine (Pedro de Cordoba), but spy Charlotte Ronnell (Dorothy Tree) is spotted fleeing the residence.

Due to a chance encounter earlier, Chan realizes that local woman Marie Dubon (Lynn Bari) is involved, and the two detectives head to her hotel.

After nearly being killed by Santelle, Charlie realizes that three clues are the key to the case: A dropped franc coin, a wooden leg, and a telephone left off the hook.