Michael Lanyard aka The Lone Wolf (Ron Randell) reformed and retired jewel thief, once again finds himself falsely accused of jewel theft by bumbling New York City Police Inspector J.D. Crane (William Frawley), whose list of usual suspects to round up has only Lanyard's name on it. Lanyard than has to start sleuthing around to find out who lifted the missing ice from an international diamond Exhibit. Lanyard has a longer usual-suspects list that includes the name of all of the non-American citizens who were attendees including a Texan. He also adds the name of Grace Duffy (June Vincent) to his list, to give him a blonde femme-fatale to give his close, personal attention. His sharp valet Jamison (Alan Mobray) thinks the name of Marta Frisbie (Colette Lyons) should also be on the Suspects List. Crane remains positive that Lanyard is the culprit.