On an ocean liner bound for New York, Simon Templar George Sanders, the Saint, rescues a fellow passenger from card cheats. The woman refuses to reveal her name and is offended when he kisses her without invitation. He later sends her a rose corsage as an apology.
The Saint learns that his friendly nemesis, Inspector Henry Fernack Jonathan Hale, has been suspended from the police after $50,000 is found in his safe. He has been framed by “Big” Ben Egan Pierre Watkin on behalf of his race-fixing gang, which Fernack was investigating. The other members of the gang — Rocky Weldon [Roland Drew], Leo Sloan [Robert Emmett Keane], Sam Reese Morgan Conway and Max Bremer Cy Kendall — each pay a quarter share of the $90,000 cost of the frame-up. Rocky Weldon has just been cleared in a trial after the testimony of his bodyguard, Pearly Gates Paul Guilfoyle, and the murder of the main prosecution witness, Johnny Summers.
Egan orders two henchmen to pick up the woman passenger when the ship arrives. Templar foils them, and the woman drives off in a taxi. He goes to see Fernack. Weldon sends Gates to rob Egan, but Egan catches the safe cracker. At gunpoint, Gates confesses that Weldon sent him. Egan orders him to lure his boss into a trap, but after Gates leaves, an unseen shooter kills Egan. Templar and Fernack meet when they both sneak into Egan’s place. The Saint finds the hidden camera and later develops the photograph. He also picks up a clue, a rose petal.
Weldon assumes Gates killed Egan and has the $90,000, despite Gates’ protestations. Templar blackmails Gates into helping him in exchange for not giving the police the photograph and telling Weldon that Gates does not have the money. However, when they go to see Weldon, they find him dead, and once again, Fernack is already there.
Templar, assisted by Gates, kidnaps Sloan, the most likely of the survivors to talk, but they are followed. When Templar leaves Sloan guarded by Fernack, Sloan is shot and killed through Fernack’s basement window. They take the body back to Sloan’s place, but the suspicious police burst in and take them by surprise. Only Templar manages to escape.
He waits for the murderer in Reese’s apartment (Bremer being out of town). He is unsurprised when the woman shows up. It is his fellow ship passenger Ruth Summers Wendy Barrie Summers, Johnny’s sister, out for revenge. He offers to help her. Templar has Gates “betray” him to Bremer and Reese. They catch him searching Bremer’s office. He offers to trade the $90,000 for his life, but insists they tell him everything. Their unwitting confessions are broadcast to the police via a hidden microphone and radio transmitter. When the police arrive, Bremer escapes by the fire escape. In the alley, he encounters Ruth. Each fatally shoots the other. Ruth makes a deathbed confession to the three previous murders, then dies before Templar can tell her something important.
