While travelling by train with his sidekick and assistant, "Goldie" Locke, for a vacation in
San Francisco, Tom Lawrence, a.k.a. The Falcon, meets Annie Marshall, a lonely little girl. Annie tells them that she is being held prisoner by her nurse, Miss Carla Keyes, and butler Loomis. Annie's story is cut short when Miss Keyes comes for her. Shortly after, the little girl rushes back to Tom to tell him she cannot wake her nurse; Keyes turns out to be dead. Tom takes charge of Annie, but the police are notified by an anonymous source that the little girl is being kidnapped. After they arrive in San Francisco, he takes her home in a taxi, but the police apprehend the Falcon. Released on $10,000 bail, posted by Doreen Temple, a complete stranger, who promises Tom she will disclose the motive behind her generosity. At dinner that evening, Doreen brings along her bodyguard Rickey, posing as a police officer. When they leave, Rickey knocks Tom out and takes him to Doreen's apartment, where she interrogates him about someone named Vantine. When he denies knowing the man, she does not believe him and has Rickey beat him up with the help of another man; Doreen lets him go, telling him to take Vantine a message: to stay away from something called the Citadel. After Tom returns to his hotel to collect Goldie, they decide to pay a visit to Annie's house, where they meet her older sister Joan who denies knowing either Doreen or Vantine. Annie claims she made up the story about being held captive, but when Tom sneaks back to the house to talk to her, she says Loomis is holding her prisoner. She takes them to Carla's room where they find a photograph of a ship's officer, signed to his wife, Carla. Loomis hears someone rummaging around in the nurse's room, but is shot dead by an unknown assailant. Returning to their hotel, Tom is confronted by Vantine, brandishing a gun. When Tom disarms him, he learns Doreen was the romantic interest of an ex-
bootlegger, Duke Monette, involved with a shipment aboard the cargo ship S.S.
Citadel. Tom visits the Star Coastal lines where DeForrest, the company's general manager, is meeting with Joan, the owner of the company. A clerk at the office alerts Tom to go to an address, which turns out to be Doreen's apartment, where she is waiting with her gang. Vantine, also lured into her trap, arrives and begins to fight with Doreen's thugs. Tom and Joan manage an escape but on his return to his hotel room, discovers DeForrest hiding in a closet. Goldie finds a newspaper article that shows that the real owner of the
Citadel is Duke Monette. That night Tom and Goldie sneak aboard the ship and find raw silk hidden among the bales of hemp cargo. Returning to the Marshall house, the little girl tells Tom that Joan has left to meet her "secret lover" on Telegraph Hill. Tom observes the rendezvous with Joan and DeForrest, who Tom thinks is really Duke Monette, confessing that he used a secret identity to protect his daughters, Joan and Annie. Fearing Doreen plans to hijack the illicit silk cargo that night, Duke asks for the detective's help. At dockside, Duke and Tom watch Vantine, Doreen and the other gang members board the
Citadel. Duke suddenly knocks the ship's engineer unconscious, and blows up the unattended boiler room, then pulls a gun on Doreen and Tom. Tom tells Doreen that Duke killed Miss Keyes and Loomis, the employees she hired to watch over the girls. When Tom warns that Duke plans to blow up the ship, Doreen and Rickey lunge forward to disarm Duke, who shoots them both, but Rickey shoots Duke, allowing Tom to flee before the ship explodes. ==Cast==