Otto Romburg, a toy store owner, is working on his battlefield dioramas when MacGyver calls him from the former Stasi headquarters in East Berlin. He tells Otto that he's found a file on Maria, Otto's long-lost granddaughter. Otto is unaware that someone is watching the shop using advanced surveillance equipment and armed with a crossbow. After hanging up, Otto looks at a doll and remembers crossing the border with his daughter Maria, only for the guards to kill her father and capture her while he escapes with her doll.
At a bar in East Germany, MacGyver meets with Rolf Mossel, a member of the citizen's freedom committee. The man has determined that Maria is now a teacher in Leipzig. MacGyver takes a train to the school where Maria works. She tells MacGyver to tell her grandfather that to her, he is dead. MacGyver insists that Otto loves her and wants her to live with him. He's unaware that man is monitoring their conversation. Maria refuses to go back with MacGyver and he gives her a letter from Otto and says he'll be in town until the next day, and she can contact him at the hotel. Once MacGyver is gone, Maria reads the letter. Outside the school, MacGyver spots the man following him and taking pictures. MacGyver ducks around a corner and grabs the man when he follows. The man manages to break free and the two struggle. MacGyver ends up thrown into a garbage can while his follower escapes in a beat-up old car. However, MacGyver spots the tape recorder the man was monitoring Maria and MacGyver's conversation. He meets with Rolf and notes the equipment is highly advanced and wonders if the Stasi is somehow involved. They're interrupted when Maria arrives and says she wants to go with him. She admits the letter makes Otto sound very heartsick and she wants to decide for herself once she sees him. Once they leave, MacGyver's attacker approaches "Mossel," addresses him as Huber, and says that their plan is working and they'll soon have the gold.
MacGyver and an enthusiastic Maria arrive in the States and go to Otto's toy store. Grandfather and granddaughter embrace and MacGyver says he'll be back later to take Maria to Immigration to take care of her paperwork. Huber and the East German agent, Weise, arrive in the apartment across the street and meet with their surveillance operative, Kurt. In the store, Otto gives Maria her doll back. In the apartment across the street, Huber believes that Otto knows where the gold is and they should wait until Maria finds out where the gold is. They're all ex-Stasi agents desperate for money now that they're out of work.
At the Phoenix Foundation, MacGyver comments to Pete that Maria acted like an experienced traveler despite the fact she's never been out of East Germany. Pete has Willis check the recording equipment and find any fingerprints. MacGyver also asks Willis to run the photo of young Maria through the ChildFinder program to see what she'd look like at her current age.
Otto and Maria leave the toy store and Otto considers closing the store and traveling the country together. Maria hints that it would take a lot of money and Otto says that he has something saved away. They go to Otto's nearby apartment and the ex-Stasi agents focus their surveillance equipment there. Maria continues to ask about Otto's money. MacGyver arrives and goes up to Otto's apartment. Maria comes out, wearing an American dress, and she goes out with MacGyver. Before they leave, Maria says that in America everyone brings food in, again raising MacGyver's suspicion with her knowledge of America. In the other apartment, Weise grows increasingly impatient. Huber and Kurt go get something to eat while Weise claims he has stomach illness. However, once his partners are gone, Weise goes to Otto's apartment, kicks in the door, and demands to know where the gold is.
Later, MacGyver and Maria return to Otto's apartment with pizza and Maria thanks MacGyver with a kiss. Upstairs, Weise continues to beat Otto. Maria and MacGyver come in and Weise opens fire on them. MacGyver uses a table as a shield while Otto tells Maria to run and call the police. Weise shoves MacGyver back and hits him with a chair, and then runs outside. Maria is waiting and silences him with a blow to the throat, and then shoves him down the stairs. When MacGyver arrives, Maria claims that Weise slipped and fell. The police, lead by Captain Kelly, take away Weise while Pete arrives to confirm that Weise is ex-Stasi and the fingerprints on the recording device are his. They ask Otto what Weise wanted and he's forced to explain that the Stasi used Maria to force him to cooperate. They used the toy store as a courier drop. Maria says that they should have let them kill her. Otto explains that he relived her captured over and over and couldn't bear to lose her for good. Maria, upset, steps out. MacGyver notices the beam of the laser surveillance device that Huber and Kurt are using. MacGyver leads them out onto the stairs and tells Kelly and Pete what he saw. He stops at his truck and gets a road flare and then throws it in front of Kurt's apartment. The smoke highlights the laser beam. Kurt and Huber hastily exit, abandoning their equipment. They flee to a car and drive away before MacGyver can catch up to them.
MacGyver takes the equipment to Willis who admits it's the most advanced technology he's seen. He's still working on the ChildFinder program. Kelly arrives and informs them that Weise is in a coma, and suffered a sharp blow to the larynx. They realize only one thing could have caused the injury. MacGyver goes to the toy store to confront Maria. She denies it at first but then finally admits she did it. She mentions Weise's name and MacGyver notices. He comments that she knows karate and hates enough to kill. Maria admits that she had special training. Otto comes in and overhears their conversation. Maria explains that the Stasi took in orphans like her and trained them to become a "sparrow": a female agent trained to spy on friends and to kill. She traveled across the U.S. and Europe as an operative. She met Weise a month ago when Weise's superiors exploited East Germans for money. They converted the money to gold and shipped it to Otto's store. Otto rejects Maria as her granddaughter but Maria claims that now that she knows him, she's set aside her hate. Huber and Kurt burst into the store and tell Otto to give them the gold.
At the Phoenix Foundation, Willis finishes running the ChildFinder program and they realize that Maria isn't the girl in the photo.
In the toy store, Kurt ties up MacGyver in the next room while Huber binds and gags Maria. Otto refuses to tell Huber where the gold is so Kurt prepares to shoot crossbow quarrels at Maria. Otto insists that Maria isn't his granddaughter and they're trying to trick him. Kurt fires and narrowly misses. Meanwhile, MacGyver looks around and spots a toy tool kit and some slimy goo. He opens a container of the goo and lets it drip onto the ropes binding his wrist, making them slippery enough for him to get free.
Kurt continues to shoot quarrels at Maria. He gets down to his last arrow and warns it's Maria's last chance. Huber ungags Maria, who begs for her life. Otto insists she isn't his granddaughter and Kurt prepares to shoot. As she cries, Otto remembers abandoning her as a child and tells Kurt to stop. He explains that the gold is hidden as soldiers in the store window dioramas. They go upstairs past MacGyver and check one of the soldiers, confirming Otto's claim. Huber tells Kurt to kill Otto, Maria, and MacGyver. Kurt goes to find MacGyver and discovers he's escaped. He slips down the hallways and MacGyver, wearing a puppet animal on his hand, knocks him out. He then uses a remote to send an inflatable toy dirigible toward Huber. MacGyver then gets up on a shelf and drops a toy drum on Huber, restraining him. Pete and the police arrive while MacGyver frees Otto. Pete explains that Maria is a fraud and shows them the ChildFinder program results. Maria explains that during a mission her jaw was broken and the hospital performed reconstructive surgery. Otto still doesn't believe her, and Maria shows him where her mother stitched her doll together. She also describes the family puppy and the fact Otto let the dog sleep in Maria's bed when her parents were on holiday. Otto finally accepts that she is who she says.
Later, MacGyver is playing video hockey when Maria comes by to visit. She explains that the gold was turned over to the German government and they're going to use it to unite families. She then informs MacGyver that she'll be staying in the States and that with her skills, Pete plans to find a place for her with the Foundation. MacGyver is somewhat taken aback, particularly when she suggests they can see each other more often.