Otto Romburg is at his toy store working on his battlefield dioramas when MacGyver calls from East Berlin. He tells Otto that he's gone to the former Stasi headquarters to find information on Otto's long-lost granddaughter, Maria. After MacGyver hangs up, Otto picks up a daughter that belonged to Maria and remembers how he tried to escape over the border with Maria and her father. Otto made it, but Maria was captured and her father shot down. As he reminisces, Otto is unaware that a man is watching him from an apartment across the street.
MacGyver goes to a bar to meet with Roff Mossel, a member of the citizen's freedom committee. Mossel tells MacGyver that he's located Maria in Leipzig, where she works as a teacher. MacGyver visits Maria there but she is angry with her grandfather because she believes he abandoned her. MacGyver convinces her that Otto loves her and wants her to live with him in America. He gives her a letter from Otto and say he'll be heading back to the States the next day. As he leaves, MacGyver spots a man, Helmut Weise, following him from a distance and taking photos. MacGyver manages to ambush him but Weise escapes, dropping his tape recorder that he used to record MacGyver's conversation with Maria.
The next day Mossel goes to the station to bid MacGyver farewell. MacGyver shows him the tape recorder and Mossel admits that it's high-tech equipment like the Stasi used. Maria arrives and tells MacGyver that Otto's letter convinced her to go to America with MacGyver to meet her grandfather. Once they leave, Weise approaches Mossel, addresses him as Huber, and says that they'll soon have the gold.
Back in the states, Maria is overwhelmed by the freedom there and buys a root beer from a vending machine. They go to Otto's toy store and MacGyver leaves to deal with Maria's immigration paperwork. Huber and Weise arrive at the apartment across the street and meet with Kurt, the operative already in place. They listen in using a laser surveillance microphone as Otto gives Maria her doll back. The three men, all ex-Stasi agents, figure that Otto knows where the gold is. Weise is eager to find it out now but Huber says they should wait, and that will Maria will find the gold's location for them.
At the Foundation, MacGyver admits to Pete that he's suspicious about Maria, who is way too knowledgeable about travel and America to have been a simple schoolteacher in Leipzig. They have Willis check the tape recorder for fingerprints and use a ChildFinder aging program to compare Otto's photo of his granddaughter to Maria.
Otto takes Maria to his nearby apartment and suggests they might tour the country. Maria starts to hint about the gold and Otto admits that he has something saved away. MacGyver and goes to Otto's apartment to take Maria out for supper. The ex-Stasi agents, monitoring Otto's apartment, decide to get something to eat. Huber and Kurt go to get something and Weise decides to take matters into his own hands. He breaks into Otto's apartment and demands that the toy store owner tell him where the gold is.
Later, MacGyver brings Maria back to her grandfather's apartment. She thanks MacGyver with a kiss. They enter the apartment and Weise shoots at them. MacGyver uses a table as a shield and then rams him. Otto tells Maria to run and get the police. Weise gets past MacGyver and runs to the stairs, but Maria is waiting for him. She silences him with a blow to the throat and he falls down the stairs.
Later, the police arrive, lead by Captain Kelly. Pete has used fingerprinting to confirm that the comatose Weise is an ex-Stasi agent, and his fingerprints match the ones on the tape recorder. Otto finally admits that he was working with Weise and his allies. When Otto made it to America, the Stasi contacted him and threatened to kill young Maria unless he cooperated. They used the toy store as a courier drop. Maria, seemingly upset, insists that Otto should have let her die rather than help the Stasi. She storms out as MacGyver notices the laser beam from the surveillance microphone that Huber and Kurt are using. He goes to his truck and ignites a road flare, and uses the smoke to trace the laser beam to its source. Huber and Kurt spot him and make a hasty exit, abandoning their equipment.
At the Foundation, Willis is finishing work on the ChildFinder program. He determines the surveillance equipment is highly advanced gear such as the Stasi used. Kelly checks in to inform them that Weise suffered a sharp blow to the larynx that wasn't caused by the fall. MacGyver goes to the toy store and confronts Maria. She finally admits she knew Weise and had special training. Maria and other orphans were taken in by the Stasi and trained as covert operatives. Weise and his allies had stolen money from East German citizens, converted it into gold, and sent it to Otto for safekeeping. Otto overhears the conversation and turns on Maria, saying she's not his granddaughter. Maria explains that now that she knows him, she's set aside her hate and wants to turn over a new leaf. They're interrupted when Huber and Kurt break into the store and demand the gold.
At the Foundation, Willis reports to Pete that the photo of Young Maria aged using the ChildFinder doesn't match the face of the Maria with Otto.
At the store, the ex-Stasi agents tie up MacGyver in the store and then go to the basement to bind and gag Maria. Huber demands that Otto tell him where the gold. When Otto refuses, Kurt starts firing crossbow arrows at Maria, missing each time. Otto is unimpressed, believing it's a trick and she's not his granddaughter.
Upstairs, MacGyver manages to knock open a container of Silly Goo onto his ropes and slips his hands free.
Kurt prepares to fire one last lethal shot and Huber ungags Maria. She begs Otto to reveal where the gold is. He remembers her beginning him to come back when she was a child and relents, telling Huber the gold is shaped into soldiers, painted, and put in his window dioramas. Kurt and Huber go upstairs and confirm Otto is telling the truth, and then prepare to shoot MacGyver only to discover he's slipped away. MacGyver gets close to Kurt by hiding in a display of hand puppets and covering his fist with one of them, and then punching the man unconscious. He then sends a remote controlled toy dirigible at Huber, distracting him long enough to drop a toy drum on his arms.
Pete arrives with the police and take the ex-agents into custody. MacGyver frees Otto and Pete tells them what they've discovered. Maria explains that her jaw was broken during a mission and she had reconstructive surgery. Otto isn't sure, and Maria finally convinces him by relating a childhood incident where Otto let her sleep with her pet dog while her parents were away. Convinced, Otto embraces his granddaughter.
Later, Maria visits MacGyver at the Foundation and explains that the gold has been turned over to the German government, who plans to use it to reunite families separated when Germany was divided. She then tells MacGyver that she plans to stay in the States and Pete has offered her a job with the Phoenix Foundation. MacGyver isn't entirely happy at the news.