American smuggler Tony Dumont, who operates undercover as an importer-exporter, travels from Hawaii to Wake Island, on an airplane that is transporting valuable industrial diamonds. While in the air, Tony flirts with Pamela Vincent, a renowned author. The plane is hijacked by gunmen and forced to land on a deserted island airstrip, where the hijackers steal the diamonds and escape on a small boat. The passengers and crew are later rescued and flown to Hong Kong, and after being released by the police, who are unaware that Tony arranged the hijacking, Tony is unable to say goodbye to Pamela because she is mobbed by reporters. Tony's girl friend, Jean Blake, picks him up and they return together to Macao, where they live in the same apartment building, which is owned by Tony. At his office, Tony meets with his deputies, the devoted Boris and power-hungry Nicco, and confirms the diamond delivery with Bendesh at the syndicate for which he works. Tony then calls his friend Michael Quisto, who also works for the syndicate, to arrange shipping, and contacts Boussard, an insurer, to insure the shipment. That night, Tony goes to Mama Chang Lin's nightclub, and unexpectedly encounters Lobero, a childhood friend who now lives in California. Tony is surprised to see Lobero's guest, Pamela, who is with Commander Larabee, her date. While Jean dances with Larabee, Lobero and Tony tell an inquisitive Pamela about their adventures with Quisto on a tramp steamer when they were boys. Tony is called away on business, and while he is gone, Lobero reveals that Mama Lin raised Tony after discovering him abandoned in a bar when he was a baby. Meanwhile, Bendesh informs Tony that there has been a leak regarding the following day's shipment, and that another company is trying to under-bid Tony. The next day, Tony and his crew unload the stolen cargo but are attacked by a fleet of boats owned by the rival company. After a gun battle, Tony and Nicco dispatch their rivals with grenades. Although Jean is furious with Tony for leaving her at the club the previous night, they go out another night to a casino, where Lobero confides in Tony that he has joined the syndicate, but is hoping to operate independently. Moments later, Nicco informs Tony that Quisto was the leak, and that Bendesh has ordered Tony to get rid of Quisto. With Mama Lin's reluctant assistance, Pamela contacts Tony later that night and their friendship turns into a romance, although Pamela is leaving the country the next day. Mama Lin, who is also Jean's benefactor, insists that Jean go to Tony's apartment and inform him she is ending their relationship because of his infidelity. After Jean's departure, Quisto slips into Tony's apartment, and Tony promises to help him escape. However, Nicco and Boris are waiting for them at the docks, and when they point to a boat, Tony reluctantly directs his friend to the vessel they have indicated. As Quisto walks the gangplank, it collapses and he falls into a net. The boat pulls away from the dock, and Quisto is dragged to his death in the water. Boris fears for his own life, believing that Nicco may inform the syndicate about Tony's near betrayal, and goes into hiding. Several days later, Tony and Nicco attend a syndicate meeting in Tangiers, where Tony reassures Bendesh of his loyalty. When he encounters Pamela at a café, she abandons her date and spends the night and next day with Tony, who, encouraged by her affection and distraught over Quisto's death, plans to leave the syndicate to be with her. Tony secretly meets Lobero in Lisbon, and they agree to partner in a stolen diamond shipment without the syndicate's involvement. As part of their plot, Tony will smuggle the diamonds to Lobero in California using a false name and passport. To initiate their plan, Tony returns to Macao and hires a thug, Lagario, to pick up the diamonds. Next, Tony hires Cappy, who owns a junket, to fake his kidnapping. That night, during a meeting with Nicco at Tony's apartment, Cappy and his crew attack them and feign Tony's kidnapping. At a warehouse, the greedy Cappy and Lagario confront Tony and demand a partnership. Tony pretends to agree, but then turns on a fan to which he had rigged grenades, and flees with the diamonds. Cappy, Lagario and their crew are killed in the ensuing explosion, and Tony plants his identification on a dead body, steals a sailor suit and hires onto a ship as a merchant marine named Anton Dumonnez the next day. Bendesh suspects the ruse and orders a worldwide manhunt for Tony and the diamonds. Some time later, Tony arrives in San Francisco and surprises Pamela at her apartment, where she is hosting a book signing party. Upon reading the book jacket, which describes a romance thriller with a character based on himself, Tony tells Pamela about his new identity and that he is there for her. However, Pamela is no longer interested in him, and a betrayed Tony grabs her arms. Pamela's date, tennis champion Bob Denham, attempts to intervene, but Tony strikes him and leaves. After roaming the city for hours, Tony arrives at Lobero's home just as Lobero's body is being taken out by police. Bendesh's lieutenant, Carstairs, sees Tony and chases him through the city. Tony unexpectedly encounters Boris, who is glad to reunite with his friend. Boris consoles Tony, who realizes the diamonds are now worthless because no one will buy them, and advises Tony to flee to the Philippines and resurface in Hong Kong only when it is safe. Some time later, Tony contacts Mama Lin in Macao and reveals his plans to send for her and Jean. Mama Lin is delighted to hear from her long-lost "son," and they arrange to meet in Hong Kong. However, Mama Lin and Jean are followed by the syndicate, and are forced to go through elaborate ruses before meeting with Tony. Meanwhile, Hong Kong police learn that Nicco is in the city and put the force on alert. Tony plans to take a junket to Manila and later send for Jean and Mama Lin, but Jean insists on joining him immediately. However, while they are waiting for a boat to Macao, Tony sees Nicco and sends Jean and Mama Lin ahead to board. Tony confronts Nicco and offers him the diamonds in exchange for his life, but Nicco demands both. The ferry carrying Jean and Mama Lin leaves without Tony, who is arrested with Nicco moments later. Mama Lin consoles Jean, saying that although they had lost Tony once before, he was with them spiritually all along.