No relation to the 1935 Jean Harlow-Spencer Tracy vehicle of the same name, RKO Radio's Riff-Raff is an action-packed vehicle for aging but still virile Pat O'Brien. At large in Panama, American private eye Dan (O'Brien) hopes to get his hands on a valuable map showing priceless oil concessions. He finds himself up against a formidable cartel of villains headed by Molinar (Walter Slezak), who likewise want to get their mitts on the map and are willing to commit murder to do so. Mixed up in the proceedings is worldly nightclub singer Maxine (Anne Jeffreys), whose reputation is such that O'Brien immediately distrusts her--an opinion he has good reason to reverse as the film rolls along. Percy Kilbride provides a few chuckles as a dry-witted Panamanian taxi driver.
by Hal Erickson synopsis