AllMovie

Esther Ralston stars as Diana, the American houseguest of the stuffy Earl of Rochester (Lawrence Grant). Finding her host and her surroundings deadly dull, Diana isn't exactly looking forward to her impending marriage to the Earl's son Roderick (Neil Hamilton). When master criminal Chang-Tzo (Sojin) announces his intention to steal a valuable jewel owned by the Earl, Roderick heads to the family vault to lock up the gem. Hours pass. When Roderick doesn't return, Diana sets out to look for him. Thus is the nonplused girl plunged into an exciting adventure, replete with kidnappings, clutching hands, hidden rooms, trap doors and seemingly dozens of hulking henchmen. It turns out that this whole episode was concocted by Roderick and his pals, just to give Diana the "thrills" she's been yearning for. But with the sudden appearance of Chang-Tzo, things take a serious turn, obliging both Roderick and Diana to take turns rescuing each other from the villain's clutches.