Gay Lawrence, the debonair sleuth known as "The Falcon," foresakes his crime-solving and skirt-chasing efforts for the sake of his fiancée, Elinor Benford. To please Elinor, Gay and his assistant, Jonathan "Goldy" Locke, open a brokerage office on Wall Street, but after one day on the job, Gay is ready for retirement. He returns home from the office to find Helen Reed, secretary to socialite Maxine Wood, waiting to see him. On behalf of her boss, Helen asks Gay to attend a charity ball that night to protect a diamond owned by Mrs. Gardiner, one of the guests. Unable to resist, Gay accompanies Elinor to the ball, where he dances with Mrs. Gardiner, who slips him the diamond. Mrs. Gardiner's act puzzles Gay, but before he can question her, a shot rings out and she falls to the floor, dead. When the police arrive at the party, Officer Bates arrests Goldy, who was the only person in the room during the time of the shooting, as a material witness. Gay follows Goldy to the police station, where he convinces Inspector Mike Waldeck to free Goldy as bait to trap the killer. Helen meets them at the police station, and Gay leaves Goldy in a pinball parlor while he and Helen go to question Maxine. While Gay tells Maxine that he suspects that Mrs. Gardiner was involved with a gang of jewel thieves led by Manuel Retana, a guest at the ball, Goldy is abducted by Noel Weber, who orders him to phone Gay and demand that he turn over the diamond. As Goldy dials, Weber is felled by a gunshot and Goldy is again arrested for murder. Meanwhile, Gay rushes home, where Bates tells him that Goldy is being held for murder and Mike wants to see him at headquarters. Gay gives Bates the slip, however, and the next day, while disguised as a tramp, he tries to apologize to Elinor, who is furious because he left with Helen. Elinor icily informs Gay that she has a date with Retana later that night and never wants to see him again. Still suspicious of Retana, Gay and Helen break into his apartment, and when he returns during the middle of their search, they hide on the patio and watch as he checks behind a wall panel. After Retana leaves, Gay reaches behind the panel and finds the gun that killed Weber. Gay then goes to the morgue, where he examines Weber's body and recognizes him as the man pictured with Retana in a photograph he found in Retana's apartment. Meanwhile, as the police interrogate Goldy, Helen bursts in and confesses to Weber's murder and presents them with Retana's gun. When the gun is identified as the murder weapon, Helen tells them about Retana and sends them to a club where he is dining with Elinor. Gay phones Elinor at the club to tell her to leave before the police arrive, but she thinks that Gay is trying to frame Retana out of jealousy and warns him instead. When Gay returns home, he finds an armed Retana demanding the diamond, but he is frightened off when Helen unexpectedly appears at the door. Meanwhile, Bates has arrested Elinor at the club, and when she calls Gay from the police station, he instructs Mike to meet him at Maxine Wood's apartment. There, Maxine tells Gay that her life has been threatened, prompting Gay and Mike to promise to stay the night to protect her. Maxine then retires for the evening, and Gay and Mike listen at her bedroom door as Retana sneaks in through the window and threatens her. Mike and Gay charge into the room, but before they can capture Retana, he falls dead, a hypodermic needle at his side. Mike assumes that Retana committed suicide, but Gay disagrees and declares that Maxine killed Retana. He then explains that Maxine was married to Weber who, with Retana, comprised the jewel theft ring. When she and Weber tried to double-cross Retana, he killed Weber and was about to do the same to Maxine when she stabbed him with the hypodermic. Gay continues that Weber's knowledge that Goldy was at the pinball parlor tipped him that Maxine was involved in the ring. They all then return to the police station, and Elinor is about to forgive Gay when an attractive woman arrives and asks him for his help in solving a crime.