At the 14th Annual Convention of Private Investigators, Magnum is to receive the 'Local P.I. of the Year' award, but the event is brought to a halt when Jean Claude Fornier, the famous French detective, suddenly drops dead while giving a speech, after being poisoned. Magnum is "helped" by several fellow crime-busting acquaintances as he seeks the murderer, and becomes entangled with a gang of drug smugglers.