A mysterious map holds the key to billions of dollars' worth of crude oil, and some men will stop at nothing to possess it. Pat O'Brien stars as the hard-boiled, Panama-based private eye Dan Hammer, caught in the middle of a dangerous web of murder and intrigue. Hammer is hired as a bodyguard for a shady gentleman who has already killed a man to own the man, a chart that details the hidden location of rich South American oil fields. Then Hammer is approached by an oil company official who originally bought the map and a slick, art German named Molinar (Walter Slezak) - each one wants Hammer to steal the map for him. Further complicating Hammer's predicament is a romantic entanglement with Maxine (Anne Jeffreys), a pretty, blonde nightclub singer. Riffraff is a fantastic treasure hunt captured in rich black-and-white cinematography.