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.

Притворяясь торговцем редкими марками, мужчина преданно поддерживает жену и музыкально одаренного младшего брата как профессионального наемного убийцу.