France, 1803: 11 years after the Revolution, a royalist underground is led by a new 'Scarlet Pimpernel', the Purple Mask, who rescues nobles in distress and kidnaps Napoleon's officials for ransom, aided by the spy services of a group of lovely models headed by Laurette (really the Duc de Latour's daughter). But even she doesn't know the Purple Mask's real identity as foppish dancing master Rene...

Susan Hart, assistant to private detective Russ Ashton, is given a camera concealed in a hat box and assigned to take a picture of a woman. A gun is accidentally hidden in the box and the woman is killed. Susan is charged with murder, but Russ and his less-than-useful associate, Harvard, get on the case and prove that the fatal shot was fired by the killer from across the street.