During a first class flight to London, where Hollywood producer Gunnar Globle makes Jessica proofread a script to stop him yapping, actress Sonny Greer's bodyguard-driver-lover, Leon Bigard, dies, poisoned. Sonny cries murder as soon as she notices his precious cargo, the $2,000,000 Empress Diamond necklace, is stolen. It's found in the bag of stewardess Kay Davis, who switched flights last minute, but jeweler John Sukahara notices it's paste. Sonny denies it could be a security decoy. Together with Scotland Yard's paper-pusher inspector Errol Pogson on board, Jessica examines the passengers. She finally finds the real necklace, but disbelieves the thief's murder confession on surprising grounds.
—KGF Vissers