As the daring thief Arsène Lupin ransacks the homes of wealthy Parisians, the police, with a secret weapon in their arsenal, attempt to ferret him out.
Sydney Fox is a professor and globe-trotting "relic hunter" who looks for ancient artifacts to return to museums and/or the descendants of the original owner. She is aided by her linguistic assistant Nigel and occasionally by her somewhat air-headed secretary Claudia. She often ends up battling rival hunters seeking out artifacts for the money.
