MacGyver parachutes into Kabustan and uses a Phoenix radio tracker to locate a downed airplane. As he explores the wreckage, he hears someone whistling. Jack Dalton strolls in. MacGyver is thrilled to have him alive, but less than thrilled to be sent in to rescue Jack from another of his scams. Jack says that he's there on legitimate Phoenix Foundation business, but MacGyver wonders how he convinced the board to underwrite his plan to find the Fountain of Youth. Jack claims the army isn't interested in the area, and that there's a spring in Amakash Valley that reverses aging. MacGyver isn't convinced despite the fact Jack's eye isn't twitching. The helicopter will be there in four hours, but Jack insists on going to find the spring. MacGyver reluctantly goes along with him despite his suspicions.
Jack goes to a nearby village where he meets Mukti, a young girl who informs them that Baba, the local emir, has finally granted Jack permission to visit the spring. MacGyver prepares to leave and meet Jack at the plane, but Mukti says that Baba is expecting him as well. MacGyver still doesn't believe, but is intrigued when Jack points out that the teenage Mukti is 42 years old. They proceed as Mukti explains they are part of Amakash and govern themselves. She also informs MacGyver that Jack has offered to take her with him. At the temple, Jack and MacGyver meet with Baba. He asks why they want the water and Jack finds himself unable to spin a tale. MacGyver says they'd like to take a sample with them, and Baba points out it is forbidden to visit the stream. However, after looking into MacGyver's eyes, he gives them permission to go. As they leave, Baba notes to his aide Ram that MacGyver will assist them.
Mukti take Jack and MacGyver to the spring and Jack immediately starts drinking, while taking vaguely about rights. The earth shake and Mukti explains that some who have ventured there have never returned. The fountain dies down quickly and MacGyver figures it isn't a natural phenomena. He figures it's being diverted by a strong pump and heads upstream to investigate, despite Mukti's warnings. In the bushes, Baba and Ram watch and Baba says that MacGyver's will is strong. As Jack and Mukti go after MacGyver, Baba tells Ram that it is destined that Mukti go with them. Upstream, the trio finds a pumphouse guarded by soldiers. More soldiers spot them, but Baba steps in the way as they prepare to fire. One soldier shoots Baba, who falls to the ground. The leader, Captain Samad, tells them to spare the girl.
MacGyver and the others get Baba to a meditation cave containing an altar. He gives MacGyver permission to continue his quest, and to take Jack and Mukti with him. Mukti insists she should stay with him, but Baba says it is a minor wound and Ram will attend to him. He informs her she has much to learn of others. Outside, Jack is eager to get out with their water samples but MacGyver insists in finding out what's going on. He sneaks into the pumphouse and discovers that the water is being diverted. He puts the radio transceiver from the pipe and then slips away. They follow the signal to a mountain containing an underground base. Jack and MacGyver throw rocks to draw the guards off and then sneak in through the gate.
Inside the mountain they find a calutron: a heavy water plant capable of manufacturing nuclear weapons. MacGyver spots Dr. Liang, a Chinese H-bomb expert. They need to take proof and MacGyver goes to get some. After a few minutes, Jack gets impatient and follows him. Meanwhile, MacGyver slips into the control chamber and knocks out a technician. He then takes a tape from the security monitor, unaware that Jack has found a cart of water samples and is borrowing a few. Captain Samad spots Jack and goes after him. MacGyver returns to Mukti and realizes Jack has left. Samad arrives and captures them all. MacGyver manages to hide the tape in a garbage can before Samad's men search him. He studies Mukti carefully and she says he should never have come back. Samad discovers that Jack has a contract from the Be Young Company to buy the water rights and market them, but figures it's a cover for a spy operation. Samad also finds a letter from the Phoenix Foundation, and he thinks it confirms they're spies.
In the cell, Jack finally admits that Be Young was paying him $200,000 to get the water rights. Jack has one last test tube with a sample and MacGyver uses a piece of it to short out the door wiring. He uses the stopper to jam the door open once Samad and Liang come in. Liang demands the videotape but when they refuse, he orders their execution. As they go, Samad admits that Mukti saved his life once but he can't do anything for her. Once he leaves, Mukti explains that the much older Samad is her twin brother. As a child, he was violent and she pleaded for his life. Baba banished him from the valley instead.
Once the coast is clear, they leave the cell and recover the videotape. Samad quickly realizes they've escaped and pursues them through the plant as they head for the entrance tunnel. Using a ladder, MacGyver and Jack knock down the guards and break through the gate, then run into the valley. The trio goes to the pumphouse and MacGyver gives Jack the tape to get to the UN. He then knocks out the guard and shuts down the valve. The water backs up and MacGyver makes a hasty exit. Samad and his men open fire, too late, and the pumphouse explodes, knocking them out.
Later, the group gets Baba back to the temple and the helicopter arrives. Mukti tells Jack that she'll stay in Amakash and consider what she's learned about things outside the valley, and in her herself. MacGyver and Jack leave, while Baba notes that Jack's plans will change. Jack drops the water and says that the fountain would draw a media circus, and he doesn't want to ruin the people's perfection. However, he stops long enough to drink the last of the water.