Outside a courthouse, MacGyver is playing with a 9-year-old boy, Tommy Giordano. MacGyver knows Tommy's mother, Mary Ruth, since he first worked at the Phoenix Foundation. Mary Ruth has gotten a divorce and she and her husband Richard are both suing for custody of Tommy. MacGyver tries to assure Tommy that his parents will understand. The Giordanos come out and Richard complains to his lawyer that he couldn't get visitation rights. The lawyer points out that Richard verbally abused his wife and the judge in court. Mary Ruth tries to get Tommy away but Richard comes after them and tries to explain. Mary Ruth accepts his overture and Richard asks for a minute alone with Tommy. He tells Tommy to call him if Mary Ruth gets hysterical. Tommy mentions that MacGyver is taking him and his mother to the aquarium that afternoon.
Richard's uncle Joe Catano is meeting with his lieutenant, Paulie Rizzo. Despite pressure from a rival, Joe refuses to sell drugs to kids. Richard comes in and Joe reminds him that he tried to give him the bum's rush years ago. Richard explains that he lost custody of Tommy in the divorce and insists that it's Mary Ruth's fault. He wants Joe to help him get Tommy back and Richard says he was wrong. He tries to manipulate Joe, who is well aware of what he's up to. Richard starts to leave but Joe says that he'll help anyway. He finds out where Tommy is and says that he'll be taking the boy with him to Canada.
At the aquarium, Tommy admires the fish and goes around the corner to the shark exhibit. MacGyver and Mary Ruth follow more slowly and she admits that she's having trouble coming to grips with being on her own. They arrive at the shark tank just as two of Joe's men grab the boy. MacGyver chases after them and sees Richard drive away with Tommy as Joe's thugs knock MacGyver down and escape.
Back in the aquarium, the police warn that there's little that Mary Ruth can do until the divorce papers are completed. They advise her to wait a few days and leave.
At Joe's manor, Tommy asks Richard what's going on. His father says they're going to a ranch on Canada and Tommy will enjoy it. Joe arrives and is happy to see the boy, talking about the horses at his ranch.
At the Foundation, Pete informs Mary Ruth that they did a background check on Richard when they hired her. He explains that Joe is the head of the Catano crime family and Richard broke with the family years ago. Mary Ruth insists that Richard is taking Tommy to win, not because he cares for the boy. Tommy calls and tells Mary Ruth goodbye, saying he's going to the ranch. Richard hangs up the phone before Mary Ruth can learn anything further. As they leave, Joe introduces Tommy to Paulie before departing. Once they're gone, Paulie calls Joe's rival mobster Peter Vicaro, tells him where Joe is going, and assures the man he can get his thugs past security.
Pete gets Joe's address and sends MacGyver and Mary Ruth to meet there with George Kaplan, their FBI contact. When they arrive, Kaplan tells them that Joe is flying to Canada and the FBI can't get involved in a civil matter. He notes that Joe has been having trouble with Vicaro and has a price on his head. MacGyver insists he'll get the boy and Kaplan warns that Mary Ruth would have to go with him: otherwise it's kidnapping. Mary Ruth refuses to leave Tommy in danger and insists on going.
In Alberta, Canada, Joe's men patrol the ranch grounds and Tommy wonders why. Joe explains that someone is trying to steal what he's worked for, and tells the boy not to go outside the gate. Outside the grounds, MacGyver and Mary Ruth spot Tommy and also notice Vicaro's men. He goes to keep an eye on them. Meanwhile, Joe takes Tommy riding and the boy talks about how his mother always cries when Richard is around.
Mary Ruth and MacGyver follow the mobsters to a local motel and overhear them saying they're waiting for a phone call before they go after Joe. MacGyver checks them into the room next door by pretending to be an astrology buff and wanting the specific room number.
That night, Tommy interrupts Richard when he's making a phone call and the father snaps at his son. Joe overhears the conversation and yanks the phone out of Richard's hand. He warns his nephew not to snap at the boy and Richard explains he's planning a trip to Vienna for a new job. Joe pegs him as only being interested in himself, not Tommy, and wonders why Richard wanted him. Richard insists Tommy is his, and Joe says Tommy needs to be a kid.
The mobsters settle in at the motel and MacGyver hooks up his phone to the neighboring juncture box. He needs five minutes in the room and tells Mary Ruth to do whatever she can to get them out for five minutes. She goes next door just as the two mobsters leave for supper. MacGyver tells her to knock on the door if they come back and then goes into their hotel room.
At the ranch, Tommy is playing with a remote-controlled robot toy like the one MacGyver made for him. Once Richard is gone, Joe tells the boy that he'll be sending him back to see his mother. Tommy is happy to hear the news and promises to talk with him from time to time.
MacGyver finishes hooking up the phone lines just as Paulie calls from the ranch to notify the mobsters. They pull up outside and Mary Ruth knocks on the wall to warn MacGyver. He finishes the hookup and hides in the bathroom, and Paulie hangs up before they can answer it. Mary Ruth fakes a fight and then runs next door and asks them for help. She quickly pulls them out and MacGyver slips out while they're distracted. Mary Ruth explains that her boyfriend left and thanks them for their help. MacGyver returns and Paulie calls them. He listens in as Paulie tells them his man Tony is on the gate and they're to go in using a delivery van. Once the mobsters are inside, they're to finish off everyone inside. MacGyver tells Mary Ruth to call the police and then climbs onto the top of the delivery van.
Mary Ruth goes to the motel clerk, who informs her the nearest law enforcement is a Mountie base. She orders him to call and then goes after MacGyver.
The mobsters pull up in the delivery van and dispose of the one guard. MacGyver grabs the guard's scarf and uses it to plug the exhaust pipe. The killers are unable to start the van and MacGyver slips into the main house. He locks the doors using phone cord wrapped around the handles. Meanwhile, Paulie takes a gun from his briefcase and prepares to shoot Joe. Outside, the scarf finally blows out and the killers proceed inside. Joe's guards go to investigate and get shot down. Paulie prepares to shoot Joe and MacGyver knocks him out. Tommy and Richard come downstairs and Joe tells MacGyver to make sure Tommy is safe. When Richard tries to run without his son, a disgusted Joe knocks him out.
The two killers break in and discover Paulie and Richard, unconscious. As they go upstairs, MacGyver spots Tommy's robot toy and bottles of alcohol. He mixes the alcohol with descaler and ammonia and mixes it in a small compartment in the toy. He then rigs the wires to spark, setting off a smoke screen. MacGyver places the toy at the base of the stairs and hides. When the mobsters come down, they kick the toy aside, separating the wires. MacGyver activates the toy and bumps it into the stairs, placing the wires back together. He then steers it next to the hitmen and sets off the spark, engulfing them in blinding smoke. MacGyver and Joe knock them out while Mary Ruth pulls outside and runs into the house. She spots the inside man, Tony, as he goes down to the basement. He prepares to shoot MacGyver and Joe and Mary Ruth knocks him out with a frying pan. Tommy runs into her arms as mother and son are reunited. Joe tells Mary Ruth to take her son home and he'll make sure Richard doesn't bother her any more.
Later, Mary Ruth and Tommy visit Pete and MacGyver at the Foundation and she thanks them for teaching her to be independent. They warn her that they'll soon have to worry about Tommy hitting puberty.