In a section of New York called “below the deadline,” where there are more diamonds per square foot than in any other part of the world, gangster Flash Ackroyd schemes to steal an incoming diamond shipment from Abrams and Co. by seducing secretary Molly Fitzgerald. One night, as Molly leaves work, Flash’s henchman, Spike, tries to pick her up, but is forced to drive off when he sees Molly’s boyfriend, police officer Terry Mulvaney, approach. Flash then bets Spike and his partner, Diamond Dutch, $500 each that, by the following evening, he can get Molly to tell him when the diamonds will arrive. Impersonating a buyer, Flash learns from Abrams that more stones will be coming on Thursday and then gives Molly a ride home, where he meets Terry. Returning to Diamond Dutch and Spike, Flash collects on their bet and announces his plans to “pin the rap” on the diamond heist on Terry. Tricked into meeting Molly at the office on Thursday night, Terry, who is known as “brick-top” because of his conspicuous red hair, is seen by two officers on his way to Abrams’ office. Flash’s henchman, Al, knocks him out, ties him up, and leaves him in an alley. Meanwhile, Spike, Flash and Diamond Dutch rob the office with handkerchiefs over their faces. After Flash kills a guard, Molly hears him use an Irish brogue similar to Terry’s and, lifting his hat to reveal red hair, thinks Terry is one of the robbers and faints. After Al cuts Terry’s ropes and leaves, Terry revives and stops a police car for help, but is arrested. Terry escapes and boards a train, which crashes, and he is again knocked out. When he revives, he places his wallet in the pocket of a dead man whose face is unrecognizable, and is assumed dead. He then has plastic surgery performed on his nose, dyes his hair, and assumes a new identity. Meanwhile, Molly is suspected of being in on the heist by the police and the insurance investigator, Pearson. Because of the allegations against her, Molly is unable to find work, so Flash offers a job as a cashier in his club, the Alhambra. Terry, meanwhile, introduces himself to Pearson as Terry’s brother Ed from Colorado who is in town to clear Terry’s name. Pearson procures Terry’s fingerprints, however, and determines his real identity. Believing he was framed, Pearson offers to help Terry investigate, but warns him not to let Molly know, lest she inadvertently give him away to the police. To ease Molly’s mind, Terry visits her as Ed and tells her that Terry is back in Colorado. Overcome with passion, Terry kisses her forcefully, which troubles her, as she realizes she is attracted to him. Flash, seeing Molly with another man, becomes jealous and, as an insult to “Ed,” mimics an Irish brogue. He then orders Al to shadow “Ed,” and Al follows Terry to Artie Nolan’s gym, where he works out as a boxer. Terry hears Al whistle the same Irish tune he heard when Al knocked him out in the alley and tells Pearson about his discovery. When he learns that Al is Flash’s chauffeur, Pearson realizes it was Flash who framed Terry. Molly, meanwhile, finally realizes that Ed is Terry. She acts indignant at first, but then makes up with him in a taxi. However, the taxi driver works for Flash and brings them to him. As Flash sends Molly and Terry to be killed by Al and the driver, the police invade and capture the gang. Terry fights Flash, and Pearson shoots Al. The jewels are returned, and Terry is promoted to detective, while Abrams gives Molly a wedding ring on the house. More on Wikipedia or Mubi
Watch Below the Deadline (1936)
Spanish sub.