In New York, private investigator Bradford Galt asks his secretary Kathleen to help him catch a man who has been following him. He does catch the thug, who is carrying identification in the name of Fred Foss and says he was hired by Tony Jardine. However, his name is actually Stauffer, and he is working for Hardy Cathcart, a wealthy art-gallery owner. During the confrontation Stauffer's suit is stained with ink. Later a car rushes at Brad, apparently attempting to kill him. Brad explains to Kathleen that Jardine is a corrupt lawyer who was Brad's business partner when they lived in San Francisco. Brad had caught Jardine committing theft and blackmail; but Jardine had turned the tables, attacking Brad, forcibly getting him drunk, and putting him behind the wheel of a car. A man was killed and Brad served time for manslaughter. At the time he thought Jardine was satisfied with that, but now it seems not. The car's license plate leads Brad to Jardine, who is spending the evening with Cathcart's trophy wife Mari : they are having an affair. She remains out of sight while Brad confronts Jardine, who denies even knowing that Brad was out of prison. The two men fight and Mari callsthe police, but Brad quickly leaves the scene. Cathcart, who had hoped they would fight to the death, now arranges for Brad to be framed for murder. Stauffer ambushes both Brad and Jardine in Brad's apartment. He renders Brad unconscious with ether, kills Jardine with a fireplace poker, and leaves the weapon in Brad's hand. Kathleen and Brad have fallen in love, so she aids him in covering up the crime until he can find and incriminate the real murderer. They find Fred Foss, but he can only tell them his wallet was stolen. They manage to trace Stauffer by contacting dry cleaners until they find the one who treated the distinctively ink-stained suit. But they find Stauffer murdered: rather than pay him off, Cathcart has pushed him through a window to his death. Brad flees the scene by stealing a taxi and driving it to a taxi garage where the police will be unable to pick it out from the others. Finally Brad and Kathleen identify Hardy Cathcart as being connected to Stauffer. Brad goes to Cathcart's gallery, posing as a wealthy buyer. Taken to Cathcart's office to wait for the man, he tries to search for evidence, but Mari Cathcart happens to come in. Knowing Jardine was a womanizer, Brad guesses about the affair and tells her Jardine has been murdered. "Hardy did it", she moans, and then faints. Cathcart now arrives, gun in hand. He leads Brad to another part of the building while they talk about the crimes. Since Brad is an ex-con and a murder suspect, Cathcart simply plans to kill him and claim self-defense. But the distraught Mari Cathcart comes up behind and shoots her husband six times. Later, Kathleen tells the police that their interview will have to wait while she and Brad get married.
