On the night of 29 October, 1964, Miami Beach, Florida, hustlers Allan Dale Kuhn and Jack Roland “Murph the Surf” Murphy break into New York City’s American Museum of Natural History to steal the valuable “Star of India” sapphire and other precious gems. Sometime earlier, their friendship begins at a beach hotel, where both men provide swimming lessons, massages, and “stud” service to wealthy women, as well as steal their jewelry. When Jack sells one of his jewels to Allan for $10,000, he discovers that his partner is in a much higher bracket of thievery, despite his humble apartment. Allan lets Jack accompany him to a meeting with local black market buyer, Max “the Eye,” who pays Allan $20,000 for the jewel that Jack sold him for $10,000. Later, at Max’s beachside estate, Max informs Allan that a man in Peru is willing to pay a huge amount of money for the 563-carat Star of India, the world’s largest black sapphire. Over the next few weeks, Allan and Jack spend more time together, surfing and dating women. Allan falls in love with Ginny Eaton, a former flight attendant, but she loves Jack, despite his poor treatment of her, so Allan settles for an on-again-off-again relationship with Sharon Kagel, a high-class prostitute. Allan also teaches Jack how to evaluate jewels and find their flaws. He takes him on a speedboat ride through the wealthy section of Biscayne Bay, identifying the people who live in the beachside estates and the jewelry they own. One day, a local insurance man, Bucks, hires Allan and Jack to rob a mansion, but during the break-in they set off a silent alarm, which alerts policeman Hopper Magee. As they flee the grounds and escape in Allan’s speedboat, Magee calls ahead to the Biscayne Bay patrol boats, but Allan’s knowledge of bridges and narrow waterways lets them evade their pursuers. Later, Allan, Jack, Ginny, and Sharon sail to the Bahamas and check into an exclusive hotel. Using a duplication device, Allan creates a master key from their room key, and they steal jewelry from other guests. Returning to Miami, they drop a jewelry-filled plastic bag into the water outside the marina for safekeeping. Magee and another policeman arrest both men as they dock, but there is no evidence to hold them in jail. When Allan, Jack, and Ginny take Sharon to the airport for one of her out-of-town clients, Allan makes a last-minute decision to take another plane to New York City and steal the Star of India and other valuable gems at the Museum of Natural History. At a hotel, Allan throws a party, and becomes disturbed by the way Jack ignores Ginny, slipping away with another girl named Edna. Later, Allan, Jack, Ginny, and Edna’s roommate, Sally Nash, visit the museum, where Allan and Jack determine its weak spots and unlock a window. That night, Allan and Jack rappel down a rope from the roof to the unlocked window, break into the protective glass cases, and steal the gems. Expecting an alarm, they save the huge sapphire for last and prepare to hurry back up the rope, but the museum’s management allowed the alarm wiring and batteries to corrode. Both men are shocked to find nobody responding to their crime. They return to Miami and play marbles with the jewels on the carpet of their hotel room. The next day, Special Agent Arnie Holcomb and his men raid the hotel room and find nothing. However, since they know Allan and Jack were in New York City during the robbery, they arrest them. Meanwhile, New York County Assistant District Attorney David Hauser tells his men he wants the jewels back at all costs. When Avery, Allan’s attorney, bails him and Jack out, Special Agent Holcomb immediately re-arrests them. Other federal agents arrest Ginny because she held Allan’s briefcase on the airplane from New York City to Miami. Though one policeman, Sgt. Bernasconi, tries to implicate her as an accessory, Ginny remains quiet out of loyalty to Jack, and Bernasconi is forced to release her. Allan and Jack throw a party at a bar and are treated as heroes. When Ginny arrives, she is disturbed to find Jack making love to another woman. Jack tells Ginny he is leaving her because he will probably go to prison, but he will assure she is financially secure. Ginny leaves, despite Allan’s attempt to catch her eye. When he later goes to her room, he finds Ginny dead from an overdose of barbituates, along with a note telling Jack she is doing what he wanted. Mourning her death and tired of Jack’s callousness, Allan takes a deal offered by Asst. D.A. Braun: only one year in prison in return for all the stolen jewels. Jack objects, but since Allan is the only one who knows where the jewels are hidden, there is nothing Jack can do. Both men take the deal.