MacGyver arrives home to find music playing on the stereo but no one there. As he goes to see if someone is inside, ex-con Earl Dent comes in, realizes the stereo is off, and turns it back on. He walks out of the room and a confused MacGyver comes back and turns off the stereo. Earl finally notices him and says he needs help getting back into training for boxing. MacGyver says that he hates boxing but Earl just wants training. He also needs a character witness and he has no one else to turn to. MacGyver gives in
Earl takes MacGyver to the department of children's welfare to meet his daughter, Veronica. He tries to introduce MacGyver, who insists that she be called Ronnie. They go inside and meet with the counselor, Clarice Miller, who says that Ronnie has been acting up for years. She insists that Ronnie needs a stable environment and Earl asks for MacGyver to testify. MacGyver realizes that he has to put a roof above both their heads. Mrs. Miller isn't thrilled to hear that Earl plans to box for a living and already has a $25,000 match lined up against Crazy Eddie Jackson. MacGyver isn't thrilled to hear that Earl is telling the counselor that MacGyver will be training him. Mrs. Miller gives Earl a chance but warns that if he doesn't succeed, Ronnie will go back to her foster parents. Outside, Earl admits that he burned his bridges behind him and can't train at a gym. They discover Ronnie stealing candy from a vending machine. When Earl tries to lecture her, Ronnie throws back his own criminal past.
MacGyver returns to his loft and starts turning the garage into a gym. Earl takes Ronnie with him to get some food at the grocery store. Ronnie starts to relax around Earl, who bumps into a car while they're playing around. The owner takes offense and Ronnie comes to her father's defense. As they go, Ronnie says that Earl could have taken the man but Earl insists there are other ways to handle the situation. He discovers that Ronnie lifted some wrestling cards and she wonders why he suddenly wants custody of her. Earl admits it was his fault and insists he wants a chance to make up for the time they were apart and then goes back to pay for the wrestling cards.
Earl and Ronnie arrive to find that MacGyver has built a gym out spare parts. MacGyver has built a punching machine and turns it over to Ronnie to use on her father, starting with a sucker punch.
Bart Riggins and his assistant, Bailey, arrive at the loft. Riggins, Earl's old manager, talks about how Earl could have been a champ but never listened to him. Earl sends Ronnie upstairs and Riggins reminds Earl the deal is to dive in the eighth round. MacGyver comes down to see what's going on and Riggins explains that he managed Earl for five years. Once they leave, MacGyver reveals that Ronnie didn't go upstairs and they go looking for her. MacGyver finds her sitting on a street corner and explains that he ran away from home once, and he figures Earl is trying to protect her. He suggests Ronnie give Earl a little time and she considers it.
Earl arrives and demands to know where she has been, and she says she ran away and figures Earl is running away from fighting. He insists there'll be a fight and takes her to a gym to show her a poster. MacGyver notes he's not the main event but Earl admits that he's been away a while, Ronnie notes a pro wrestler, Herman the German, and he gives her tickets. Earl insists that wrestling is fake but Ronnie wants to look inside the gym. Stimson, the owner, tells him to get out but Crazy Eddie taunts Earl about his bad parenting and says he doesn't want the $4,000 and will fight for free. Earl gets into ring and MacGyver tries to break them up, but ends up with a damaged nose. Stimson breaks up the fight and MacGyver manages to stagger out. As they go, Ronnie secretly takes a pair of gloves from Crazy Eddie's bag.
That night, Earl tucks Ronnie in and she apologizes for doubting him. She realizes he really wants her around. Earl goes out and MacGyver and demands to know why he's lying about how he's getting $25,000 when the match is only for $4,000. MacGyver suggests that maybe he doesn't deserve custody and Ronnie will figure it out eventually. A frustrated Earl gets up and leaves.
The next morning, Earl is in the garage when Ronnie comes in. She shows him the gloves that she stole and says she'll take them back. Earl ignores her and starts training and Ronnie runs away. Later, Earl goes to the machine shop where Riggins runs his bookie operation and tells him that he's not going to throw the fight. He leaves and Riggins tells Bailey to get Ronnie so they can use her to force Earl to throw the fight.
Earl goes back into training and tells MacGyver what he's done. Ronnie returns and Earl says that he was worried but knew she would make the right decision. Father and daughter train and Earl is finally in shape. The day before the match, MacGyver takes off on an errand and Bailey and Riggins go in to capture Ronnie at gunpoint. Ronnie realizes that Earl was willing to lose to get the money to keep her. Riggins tells Earl to throw the match and leaves with Ronnie.
Earl and MacGyver arrive at the ring for the match. MacGyver realizes that Ronnie isn't there and wonders what is going on. Riggins is holding her in a cage on a forklift at his machine shop while he sits in his upstairs office and listens to the match on the radio. Earl has to hold back to keep from beating Crazy Eddie. MacGyver scans the crowd and realizes that Riggins has Ronnie. Earl tells him to leave it alone but finally says that Riggins has his bookie operation at the machine shop across the street.
MacGyver sneaks into the machine shop via the roof and climbs across the rafters and descends a support pillar. Ronnie asks Bailey to turn up the radio so she can hear the match. He starts up the forklift and the noise from the radio covers Ronnie's escape. As MacGyver gets Ronnie out, Bailey sees them and opens fire. MacGyver turns on a crane machine and moves it forward as cover, and then smashes the crane arm into the office window, trapping them. MacGyver and Ronnie run to the arena just as Earl goes down. Ronnie yells at him to get up and Earl, inspired, gets back up and takes Crazy Eddie down. However, the judges rule in Crazy Eddie's favor. Ronnie insists they were robbed but Earl says it's okay, and Ronnie admits she loves him.
Later, Earl is pacing the boxing ring and worries that what little money he made won't satisfy Child Services. Ronnie refuses to go back to her foster parents and hopes that Mrs. Miller will give them more time. Herman the German, who has been watching the fight, comes in and says he wants to offer Earl a job as a professional wrestler. When he offers Earl a $30,000 advance, Ronnie leaps at the offer and Earl listens to his trainer.