Tony Seymour and his partner, Gaby Ramarios are a dance team who perform an Apache specialty number, which ends with Tony, via a steel waistcoat with a scabbard arrangement, getting a knife plunked into his back but he is unharmed. Gaby is an expert knife thrower. They are auditioning for parts in "La Nouvelle Revue" which is to open in three weeks at the Alhambra of Paris. The star is Yvette Delange, described as "a beautiful woman who could not hide with the most perfect makeup the ravages of time." She also does not like rehearsals, but perks up at the sight of Tony. Alphonse de la Riviere, once a great star but now just an assistant to the producer, Morel, winces when he hears this. Later, Yvette sends Alphonse to fetch Tony to her dressing room, and informs Tony that Gaby is not invited. Tony accepts her invitation. Gaby is not pleased. Yvette is found murdered, stabbed with a knife belonging to Gaby. And Gaby is charged with murder. Tony's mission now is to clear Gaby and find the real killer. Tony's suspects include Morel, Alphonse, Dubec the concierge and possibly Ninette Duval, a member of the chorus, who has her eye on Tony. She is also the only one who knows that Tony and Gaby are married.