MacGyver is at his apartment training with a friend, Lisa Chan, who is hoping to one day open up her own martial arts dojo. She gets a call from a man who wants to invest in her studio and she ask MacGyver to pick up her 14-year-old brother Paul from a birthday party while she goes to San Francisco. MacGyver agrees but Lisa warns that Paul has been acting wildly since the last time MacGyver saw him, and is asking her awkward questions about their parents' death. MacGyver promises to take care of Paul and makes sure he can still recognize him by the white streak in his hair.
In Chinatown, Dr. Shun Wei arrives at a restaurant to meet with owner and businessman Ston. Ston tells Wei that he has found the Wish Child and introduces him to Paul, dressed in traditional Chinese robes. Wei is there to test Paul on behalf of his employers. He gives Paul an ancient rock and Paul holds it in his hands over a brazier. There's a burst of smoke and Paul lets gravel fall from his hands, revealing a block with Chinese writing on it. Wei recognizes the writing as the Sign of the Wish Child and bows to Paul.
MacGyver arrives at the restaurant but Ston's man Ji blocks him from entering. MacGyver leaves but borrows an RC control, puts a dragon head mask on it, and runs it past Ji, distracting him. MacGyver slips in and sees Paul, and calls out his name. Ston's people go after MacGyver while Ston gets Paul out the back and Wei drops the block. Ji steps on the block as he comes in, and then knocks out MacGyver, while Wei picks up the block and flees.
MacGyver wakes up inside a crate filled with Chinese firecrackers. He uses the glass case from his wristwatch to focus the sun on a firecracker use and blow open the side of the crate. He nearly falls to his death as he discovers the crate is suspended by a crane over a freighter. The works get him down and MacGyver goes to find Paul. On a nearby ship, millionaire Lee Wenying is meeting with Dr. Wei. Lee shows Wei a chamber that he has made over into a shrine to the Wish Child. Wei shows him the block and admits that he believes Paul is the Wish Child. He wonders if Ston is to be trusted, and Lee confirms that Ston is a crook and a murderer. However, the millionaire has someone inside of Ston's entourage and isn't worried. As Wei goes, Lee admires a bust of the Wish Child... that looks exactly like Paul.
MacGyver goes back to the restaurant and finds that everyone has left. He spot the imprint of the block in the wood floor and pries up a bard, then goes to see Sam, a petty scam artist. Sam identifies the writing and explains that many of the Chinatown residents believe in the evidence. He shows MacGyver a postcard of the Wish Land's native lands that he's fancied up by attaching to a wood plaque, and then gives it to MacGyver. Sam explains that the Wish Child was reborn as a warlord's son. After a battle, the Wish Child lost his memory and his family and was sold into slavery. He purportedly has the ability to grant immortality to those whose souls are linked with him. Sam knows that Ston is running a scam, and warns that he'll dispose of his fake "Wish Child" once he gets his money.
At Ston's restaurant, Ston compliments Paul on making the switch and substituting the block with the Wish Child symbols. He gives Paul a Rolex and assures the boy he'll make enough money to help Lisa buy her martial artist studio. Paul begins to wonder if he rally is the Wish Child. MacGyver arrives and sneaks into the restaurant, and then gets Paul out. They duck into an alleyway as Ji and the others pursue, and MacGyver tries to explain how they attacked him. Paul doesn't believe it and insists he can trust Ston. He points out they're not hurting anyone and wonders if he might actually be the Wish Child. MacGyver gets Paul to agree to talk more once they get out of their current situation, and then makes a grappling hook out of an umbrella and a clothesline. Ji and his people find them and Paul agrees to go with them. Once he's gone, Ji comes after MacGyver, who knocks him down with a garbage can lid long enough to climb over the wall and cut the rope behind him.
With no idea where Paul is, MacGyver checks out the "relic" that Sam gave him earlier and finds the address of a museum on the back of the postcard. He goes there and meets Wei, who he recognizes from the restaurant. MacGyver wants to know who is paying Wei, but the doctor insists that his client has only a scholarly interest in the boy.
Ston and Paul go to the docks and Ston promises that no one will get hurt. On board Lee's ship in the shrine chamber, the millionaire asks about Paul's childhood accident and the boy relives it in painful detail. He mentions how he survived the car accident unscathed except for a white streak in his hair, and then wondered into the mountains: just like the Wish Child legend.
Lee's man Tong checks out the museum and listens from the shadows as MacGyver explains to Wei how Lee and Ston have tried to eliminate him. Wei finally breaks down and admits that the aging Lee wants the immortality that the Wish Child can offer. The millionaire plans to imprison Paul and keep him forever. Tong shoots Wei to silence him and then flees, and the dying Wei tells MacGyver where he can find Paul.
In the shrine chamber, Lee shows Paul a stone with a handprint reputed to be that of the Wish Child. Paul reluctantly puts his hand in the print, which turns out to be an exact match. As he goes to show Paul and Ston the bust of the Wish Child, Ston wonders how Paul pulled it off but the boy admits he had no idea. Once they determine the bust is an exact match of Paul, Lee tells Ston he'll receive his money and takes him out, locking the door and imprisoning Paul.
On deck, Lee gives Ston his million-dollar payoff, but then has him knocked out and tossed overboard with the gold as a dead weight. MacGyver arrives and sneaks on board the ship disguised as a deckhand. He bluffs his way past the crew and gets to the shrine chamber, where he's forced to subdue the third mate and suspend him in the air using a winch. He uses bullets from the man's gun, wraps the gunpowder in a bandanna, stuffs it into the chamber's lock, and then uses the cartridge shell as a fuse. Lee arrives so MacGyver sprays the chamber with fire extinguisher chemicals and has Paul wave the bust in the air. Distracted, Lee runs in and MacGyver and Paul lock him in and head for the deck.
Lee sounds the alarm and his guards free him. The ailing millionaire heads for the deck while MacGyver manages to trip up Tong and get Paul topside. They run down the gangplank and Lee comes after them, begging Paul to return. Halfway down he clutches at his chest and falls into the netting below, dead from his belief in the legend.
Later, MacGyver and Paul enjoy pizza at MacGyver's apartment when Lisa arrives and wonders how the birthday party went. MacGyver just says that it was outstanding.