Daniel Sims arrives by plane at the U.S. Virgin Islands. Casino owner Jack Catlin greets him and Sims assures Catlin that he has the $60 million in stolen diamonds. Sims is worried that the police may be after him but Catlin says he has nothing to worry about. Catlin takes a look at the diamonds and then ruthlessly guns down Sims.
MacGyver travels to Washington, D.C. to meet with Senator Rhodes. Rhodes raised $60 million and converted it into diamonds as part of an African famine relief effort. Now Sims has stolen the diamonds. Rhodes' daughter Chris has tracked Sims to the Virgin Islands but has been unable to recover the diamonds. MacGyver agrees to fly down and help her.
Chris meets MacGyver at the airport and isn't sure what to make of him. She explains that Catlin is a retired soldier of fortune with a private army. He set up in the Virgin Islands five years ago and had enough money to buy a hotel-casino. They go to the hotel and watch Catlin give a fighting demonstration where he defeats three men. After the match, Catlin meets with his assistant Tiffany, who assures him that their contact in Amsterdam can fence the diamonds. Catlin wants to be ready to leave in 48 hours.
Chris takes MacGyver to her bungalow where he decides they need to steal the diamonds back. Chris is concerned but MacGyver notes that Catlin can't report something stolen if he never claimed to have it. He also notes the diamonds weigh 200 pounds, making them difficult to steal. She warns that Catlin has two high-security vaults, in his casino and in his penthouse apartment. Chris asks what MacGyver's plan is but he notes that he doesn't try to come up with a plan because things never go as planned. MacGyver plans to check out the casino vault first by cheating and winning enough money to get Catlin to show him the vault.
That night, MacGyver and Chris head to the casino and split up. MacGyver uses a paper clip and some thread to pull off a woman's dress, and then uses the distraction to steal a pair of casino dice. In the men's room he uses a shoe polisher to shave the dice to roll 7s, and then goes to the craps table. He keeps winning and Catlin soon notices him. He sends Tiffany over to check MacGyver out and he gives a fake name. Finally MacGyver hits the house limit but Catlin lets him go again. MacGyver wins but declines another throw. He switches the dice for untampered ones and drops the shaved dice in his Virgin Mary glass. MacGyver asks Catlin to show him the vault where he'll be storing his money. Catlin agrees but once outside, Catlin gets the shaved dice from the glass and has his men take MacGyver to his office. Chris "accidentally" trips the guards and MacGyver makes a break for it. After securing a door with a floor cleaner cord, he knocks the valves off of two compressed air cylinders to propel a bar cart at two other security guards. MacGyver makes it outside and leaves with Chris.
The next morning, Chris is enthusiastic about their chances after her night of adventure and briefly holds MacGyver's hand before letting go. Since the diamonds aren't in the casino vault, they plan to break into Catlin's penthouse apartment. Chris warns that there's a security camera watching the door. MacGyver figures he has a way to get the diamonds out but it'll be noisy and he needs a loud distraction. He sets Chris up with a phone magnet in her high-heeled shoe and a ring with a sharp point to mark cards. He tells her to set things up so the customers are rioting by 2:10 a.m.
At the casino, Chris goes inside while MacGyver takes a downspout from a drainpipe and goes in disguised as a technician. He uses an alarm clock to rig the wiring to short circuit at 2:10 a.m. and then rigs a makeshift device to scramble the security camera using a coat hanger, duct tape a compact mirror, and string. He put the device on the camera and then picks open the lock on Catlin's door. When the guards come to investigate, MacGyver uses the string to pull the device off the camera, leaving no trace he was there.
Chris plays at the roulette table and Catlin notices and comes over to flirt with her. Meanwhile, MacGyver finds he has to pass through an archway to enter Catlin's apartment. Using cigar ash, he spots the laser beams and uses two cables from a fiber-optic sculpture to bypass the laser beams and slip through. He finds the vault but no signs of a lock or combination. Spotting Catlin's mynah bird, MacGyver gets an idea.
Catlin is giving Chris gambling tips when his security men notify him the intruder alarm in the penthouse has gone off. He goes up there with his men but don't find anything except the Mynah bird out of its cage. He puts it back and then opens the vault to check on the diamonds, using a handheld remote that gives off four specific tones. Finding nothing missing, Catlin goes back to the casino. Once he's gone, MacGyver emerges from the closet and uses four wineglasses and some wine to generate the musical tones to recreate the correct sequence.
Downstairs, Chris slips her foot with the magnetized shoe beneath the roulette wheel. The ball bounces, and one of the customers notices and complains. She then goes to the blackjack table, marks a card with her ring, and points it out to another customer. Meanwhile, MacGyver gets the diamonds out of the vault and takes them to the window. He attaches the downspout to the drain pipe, and then prepares to pour the diamonds in using a plastic flower petal from a sculpture. Downstairs, Chris heads for the exit but Catlin notices her and suggests she stick around while he deals with the commotion. When he leaves, she slips another magnet onto a slot machine, and the power goes out at 2:10 a.m. The lights go off and the slot machine dumps money onto the floor. Once the noise begins, MacGyver pours the diamonds down the drain pipe. Chris runs to MacGyver's car and opens the trunk, and the 200 pounds of diamond pour into the trunk. However, Catlin figures out that Chris was responsible and goes outside. She drives in one direction but Catlin's men cut her off, while MacGyver leaves in the other direction.
Back at the bungalow, Catlin calls MacGyver and offers to trade Chris for the diamonds. MacGyver follows his directions and meets Tiffany in a park. She directs him to an airfield where Catlin is leaving for Amsterdam. Chris and MacGyver are reunited as Catlin's man drives the car with the diamonds up the ramp and into the plane. As Catlin and his men go up front, MacGyver has Chris scratch Catlin with the sharp ring she used on the cards. MacGyver shoves Catlin into the cockpit and bars the door. Catlin orders his pilot to ascend, figuring the lack of oxygen will knock MacGyver and Chris out. MacGyver quickly improvises and attaches cargo chutes to the car. He and Chris get in and drive out the back of the plane. The chutes open and the car descends to safety.