At Los Angeles Harbor, a black-clad figure breaks into a shipping company, Jade Dragon, via the roof. In the office below, company vice president Raymond Ling comes to visit his boss, Adam Chung, and brings tea. He informs Mr. Chung that Pete Thornton and MacGyver are running an hour late. Raymond is mildly concerned that someone is trying to take over the shipping company, and hopes Pete and MacGyver can help. Raymond leaves and the intruder climbs down the side of the building, hangs outside the window, and fires an exploding crossbow bolt at Chung. He ducks just in time as the explosion destroys the rear wall. The figure descends to the ground below and slips under a cargo carrier driven by an accomplice as it leaves the grounds. Once outside at the dock, the intruder removes her clothing to reveal Tiu, an attractive woman in a one-piece swimming suit. She descends into the water and swims away.
MacGyver and Pete meet Raymond at the hospital. Mr. Chung isn't doing well and has been asking for them. Raymond insists he doesn't suspect anyone but Pete notes that a Hong Kong cartel is looking for anything that can be used for fast profit. They can use an established shipping company to ship anything illegal anywhere in the road. As the sole owner, Chung's death leaves it open for takeover Pete and MacGyver enter Mr. Chung's room and he says there is only chance to stop the takeover. He has a grandson, his only heir, and they should bring him only if he wishes to come. Chung informs them that his grandson is at a monastery north of San Francisco.
MacGyver goes to the monastery and meets Chung's 14-year-old grandson, Luke. He tells Luke of his grandfather's condition and his financial status, and gives him the choice to come or not. MacGyver thinks it'd be a mistake and Luke would be safer there, but Luke prefers to see his grandfather. He goes with MacGyver to the hospital but Chung has slipped into a coma. An intern, Steve, calls the local head of the cartel, Alasdair, who is meeting with... Raymond. Raymond is also surprised to hear that Chung has a grandson. Alasdair tells Raymond to have his man Wayne kill Luke and make it look like a mugging.
That night, MacGyver watches as Luke uses jher-jun acupuncture techniques to help his grandfather. The doctor has them leave and MacGyver takes Luke down to the parking garage. Wayne and his men cut off their escape and move in. MacGyver grabs a metal pole and uses it as a staff while Luke demonstrates his martial arts technique, taking out the majority of their opponents. Their assailants run off.
Raymond reports to Alasdair that Chung has revived, but he has a poison he wants Steve to administer in Chung's IV. Steve balks at killing, but Tiu arrives to threaten him if he refuses. Tiu reports that Wayne has informed them of his failure and that now she plans to dispose of Luke.
At the hospital, Chung asks if Luke remembers his father, Chung's only child. Chung arranged for Luke to be sent to the monastery when his son died. Luke insists that Chung owes him nothing. When visiting hours are over, Luke goes back to his grandfather's house. At the shipping company, Pete and MacGyver examine Chung's office for clues. MacGyver notices that one of the workers has a wrench similar to one that Wayne was using when he attacked. The guard remembers that Wayne, who matches MacGyver's description, worked there until a couple of days ago. They get an address from the computer and go to find him.
At Chung's house, Luke checks his grandfather's computer and finds a Space Invaders
game. He's interrupted when Tiu arrives and claims to be the niece of a friend of Chung's. She has a get-well gift, two lovebirds in a musical cage, and Luke tells the guard to let her in. They check her for weapons and then let her in.
Pete checks the records and discovers that Wayne flew in from Hong Kong with a young woman two days before he got a job at Jade Dragon. He checks the company files to find who Wayne used as a reference while MacGyver heads to Chung's house.
Tiu delivers the lovebirds and talks to Luke about his life in the monastery. She wonders how he could have had such a sheltered life and Luke notices that she's been hurt in the past. When he goes to get more tea, Tiu activates a CO2 dart projector in the base of the cage, designed to shoot darts in all directions. When Luke returns, she says she has to go and wishes him well. Outside, MacGyver arrives and notices Tiu, and realizes something is wrong. He drives inside and runs into the house as Luke turns on the musical mechanism. MacGyver spots the trap and gets Luke down just in time. MacGyver notices that she left her purse and opens it, only to discover a cobra inside. Luke kills it with a single well-thrown dart.
Chung takes a turn for the worse and Luke and MacGyver are called to the hospital. By the time they arrive, Chung is dead. Luke examines the body and declare that his grandfather was poisoned.
Back at his grandfather's house, Luke performs a ceremony while Pete increases the security. They found Steve the orderly, dead in his car, and figure that's how Chung was poisoned. The coroner's report indicate the poison was undetectable by normal means. They go to ask Luke how he detected the poison but find that the ceremony he was performing was a vengeance ritual. The poison is sold in Chinese herb shops and Luke would know it, so MacGyver goes to check them out.
Alasdair berates Tiu for her failure and comes up with a new plan: they're to capture Luke and force him to sign over the company.
MacGyver searches Chinatown and spots Luke coming out of a herb store. MacGyver warns how dangerous it is and Luke agrees to come with him after MacGyver checks the last two shops. Raymond and Tiu capture them at gunpoint and take them to a shop. Raymond locks them in the cellar and leaves with Tiu. Once they're gone, Luke admits that he's too naive. MacGyver checks the walls and finds boards with Chinese writing on them. Luke translates them as a plea for protection and MacGyver realizes Chinese laborers who dug escape routes throughout the city up until the early 19th century placed it there. He takes apart a radio and uses the speakers to project static as makeshift sonar.
MacGyver finds the entrance to the secret passage just as Alasdair comes down to the cellar. They hide the speakers and Alasdair offers Luke the chance to sign over the company and go back to the monastery. Raymond takes over the company and everyone wins. When Luke refuses, Tiu prepares to shoot him but MacGyver asks for a couple of minutes to convince Luke. Alasdair gives them five minutes. Once they're gone, MacGyver and Luke get the entrance open. MacGyver shorts out the light bulbs in the cellar and they proceed down the tunnel. They go out through a door at the other end and bar it behind them. They find themselves in an old opium lab with a small waterfall and MacGyver comes up with a plan. He has Luke cut out pieces of opium wrapping paper in 4' lengths and then break off wooden struts to make cross bracing, while MacGyver spreads mud and soot on the paper.
Alasdair, Raymond, and Tiu return to the cellar, realize MacGyver and Luke are gone, and soon find the escape tunnel. They proceed down the tunnel and Tiu shoots the door open. They enter the opium lab and find no one there. The trio split up to search. Tiu checks out the waterfall and spots MacGyver's Swiss Army knife at the base. Raymond comes over and MacGyver and Luke jump at them from the side. They knock out Tiu and Raymond but Alasdair fires at them. MacGyver and Luke duck for cover and Luke uses the bellows from a stove to blow ash into Alasdair's face, blinding him long enough for MacGyver to disarm him.
Later at Jade Dragon, Pete and MacGyver congratulate Luke as he dons a suit and takes over. Pete assures him that while the Phoenix Foundation are technically the trustees, they'll back anything Luke does. Luke plans to do what he thinks is right, but admits he has a lot to learn.