MacGyver breaks into a semi hauling teddy bears to find the one that contains a bio-toxin sample meant for terrorists. As he escapes with the vial, two longshoremen spot him and give chase, cornering him an alley. Before they can kill him, a biker emerges from the next-door tavern: Earl Dent. He knocks out the two men and helps MacGyver to his feat. Earl admits that he's changed since the last time they met, but quickly leaves when he hears police sirens.
MacGyver drops the vial off at the Phoenix Foundation laboratories so Pete can identify it. He's busy putting in eye drops but says that he's just doing it because his eyes itch. MacGyver goes out and finds Earl waiting for him. The ex-con wants MacGyver to come with him to his first meeting with his parole office and provide testimony. MacGyver notes that he doesn't really know Earl that well but Earl insists.
At the Corrections Department, Earl and MacGyver meet with Montana. She's not impressed by his story of wanting to turn over a new leaf and points out that he doesn't have a job or a place to stay. MacGyver reluctantly volunteers to put up Earl at his place and Montana, impressed, offers to find Earl a job at a Chicken Habit. As they talk, another ex-con listens in and then calls Jerry Kluge to tell him that Earl has a job.
Earl starts working at the fast food restaurant, and MacGyver comes by to visit him. When a man comes in to complain and manhandles his own son, Earl grabs the man and gives him a demonstration of what it feels like. Once the man has left, Earl admits to MacGyver that his father used to treat him the same way.
That night, Earl is leaving when he finds Kluge and his fellow bikers outside waiting for him. Kluge wants Earl to help him get revenge on the man who put them both in prison, a drug manufacturer named Hinkley. Earl is the only one who knows where he keeps his drug manufacturing operation. Earl insists that he's done with crime and tries to walk away. Kluge draws a gun on him but Earl disarms him, takes out the clip, and throws the gun in the garbage. However, once he's left, Kluge has his lieutenant, Rote, carefully take out the gun without smudging Earl's fingerprints.
The next day, Earl goes to the Corrections Department but finds Kluge and the others waiting for him. Kluge explains that he had Rote dress up like Earl, rob the Chicken Habit, and shoot the manager with the gun. Kluge says that once Earl helps them, he'll give him back the gun. He gives Earl his phone number and tells him to call at 2 that afternoon.
Earl goes back to the houseboat to pack his things. MacGyver arrives with the news about the theft and reminds Earl that he missed his meeting with Montana. Earl explains what happened, that he has to call Kluge later that day, and that he plans to ride with Kluge long enough to get the gun back. MacGyver warns that Kluge won't ever let him have the gun. Montana arrives and MacGyver tries to stall her, unaware that Earl is sneaking out through the skylight. He falls and they hear him, but he gets away before they can catch him. Montana is furious at Earl and figures he's backsliding, but MacGyver tires to explain what happened and insists his new friend has just had a few bad breaks. Montana admits that her parents were junkies and never were able to get over their bad breaks or go straight despite all their promises. MacGyver convinces Montana to give him 24 hours to bring Earl in on his own.
MacGyver calls Pete and has him trace the phone number to the Handle Bar, a known biker hangout. Pete also comes up with the name of Pete Dash, a man who knows Kluge and is still in prison. MacGyver heads for the bar on his motorcycle, unaware that Montana is tailing him.
At the bar, MacGyver goes inside while Montana attaches a radio transmitter to his motorcycle. He overhears Kluge and Rote talking about how they're still at least one gang member short to pull off their raid. Earl calls at 2 p.m. but MacGyver isn't able to overhear the call and learn the address where they're going to meet. He goes outside and sabotages Kluge's fuel line, and then works on his bike. When the bikers come out and Kluge can't start his bike, MacGyver volunteers to repair it. He does and mentions Dash's name, and after the bikers test him and he passes, Kluge asks him to ride with them so they can hijack Hinkley's crystal meth shipment.
The gang meets up with Earl, who gets a minute alone with MacGyver. MacGyver explains that they have to stop the hijacking so they can go to Montana and show her that Earl has reformed. Kluge has everyone mount up so that Earl can lead them to Hinkley's plant. They're all unaware that Montana is following them.
Earl leads the bikers to the abandoned warehouse and they find one worker. He tells them that Hinkley and his other men are out of town. MacGyver tries to convince Kluge to let the man go to give Hinkley a warning, but Kluge guns him down. The gang finds Hinkley's storage room with his cash and drugs. Kluge has his other two men, Hawkins and Wally, bring in the bikes and they discover the radio transmitter on MacGyver's bike. They figure that MacGyver is an undercover cop and Earl blames Kluge for letting MacGyver into the gang. Convinced that Earl is on his side, Kluge gives him the gun to watch MacGyver. However, Montana comes and sees Earl with the gun and figures he's crooked. She tries to arrest the gang but Kluge shoves Earl into Montana, knocking her down so he can grab her gun.
The gang ties up MacGyver, Montana, and Earl and dump them in a storage room. While they go to load up the money and drugs, MacGyver tells Earl and Montana to argue to cover the noise of his breaking a beaker to cut himself free. They argue for real until MacGyver gets free and tells them they can stop. MacGyver then uses a sprayer, a rubber hose, and a bottle of ether to knock out Rote, who is standing guard outside the door. Earl breaks the doorknob off and they realize that the bikers are between them and the exit.
MacGyver mixes an explosive out of the drug lab's chemicals and spreads it on the floor. When Hawkins comes back, he steps in the chemical but it doesn't go off on contact. The biker spots the unconscious Rote and sounds the alarm. MacGyver tackles Hawkins while Montana draws Wally's fire so Earl can knock him out. Kluge tries to escape in Hinkley's van so MacGyver grabs an air tank, sticks into the dish he used to mix the explosive, and mounts the tank on the front of Earl's trike. MacGyver then drives at the van, jumping clear just as it slams into the van and blows up. The money is blasted everywhere and they easily capture a stunned Kluge.
Later, Earl is working at the Chicken Habit when Montana and MacGyver stop by. They tell him that the police busted Hinkley. MacGyver finally tells his friend that the Phoenix Foundation is providing a grant to finance new chances for ex-convicts. Montana is going to be in charge of the program and she needs a partner to help her deal with high-control parolees. She wants Earl to sign on but he starts arguing and MacGyver slips out while the two of them bicker.