Though billed fourth in This Gun For Hire, Alan Ladd was catapulted to stardom in the role of Phillip Raven, a ruthless professional killer with a long-suppressed streak of decency. After successfully pulling off his latest murder, Raven reports to his boss, effeminate fifth columnist Willard Gates (Laird Cregar).
He collects his $1000 fee, only to discover later that Gates has double-crossed him with marked bills. This was done at the behest of Gates' boss, crooked business executive Alvin Bewster (Tully Marshall), who wants no loose ends left around to connect him with a plot to sell poison gas to the Axis.
As Raven ducks and dodges the police, detective Michael Crane (Robert Preston) is hot on the trail of Bewster and Gates. Crane talks his girlfriend, nightclub singer-musician Ellen Graham (Veronica Lake), into taking a job at Gates' nightclub. While on the train to the club, Ellen makes the acquaintance of the escaping Raven.
Gates boards the train, spots Ellen innocently sitting next to Raven, and assumes that the two are in cahoots. Later, Gates kidnaps Ellen and spirits her away to his mansion, intending to do away with her the first chance he gets. Instead, Raven, still seeking revenge for being set up, bursts into the mansion in search of Gates.
Having previously been impressed by Ellen's kindness, he rescues her, though he intends using her as hostage should the police catch up with him. As they hide out together in the rail yards, Ellen and Raven get to know each other. Learning of Raven's miserable, abusive childhood, Ellen tries to chip away his murderous veneer, hoping to reform him.
But when the cops arrive, Raven reverts to his instincts, shooting his way out of his hiding place. As Crane escorts Ellen out of harm's way, Raven rushes towards a bloody showdown with Bewster and Gates.
Based on Graham Greene's A Gun For Sale, This Gun For Hire was remade in 1958 as Short Cut to Hell, then again under the original title as a 1990 made-for-TV film.