Interpol detective Caesar Smith tracks robbers of the Royal Mint van. He travels to Rio de Janeiro, Rome and Paris and establishes the guilt of a London coffee importer.

Antonio Riccardi, a rare stamp dealer who is secretly a hired killer, pays for the violin lessons of his gifted brother Giuseppe. To meet the expenses of Giuseppe's concert debut he accepts a further job, but his decision to do so provides Detective Inspector Carson, who has long hoped to ensnare Tony, with an opportunity that might now enable him to bring about his downfall.

A little girl accidentally breaks her mother's favourite ornament and goes hop-picking to replace it.