MacGyver returns home with Pete, who wants him to take on an another assignment. An exhausted MacGyver insists he needs some rest and tells Pete no in no uncertain terms. MacGyver storms into his houseboat only to discover that Jack Dalton and Penny Parker have left him messages asking him for help. Jack wants him to help buy a ranch and Penny wants him to hear her new number she's doing at a frontier park. MacGyver erases them and puts in a tape of Gunfight at the O.K. Corral
. However, he doses off in front of the television and dreams...
A Civil War veteran, MacGyver, catches a wagon ride to the town of Serenity. He admits to the driver he picked the name at random and is looking for somewhere quiet to settle down. MacGyver gives the driver his gun as thanks for the ride, saying he carried it for four years and he's done with guns. The wagon driver reluctantly takes it and offers him a Swiss Army knife in return. MacGyver accepts it and walks into Serenity.
MacGyver stops in at a saloon and orders a bottle of milk. The local thugbus, Milt and Wilt Bozer, taunt him and a saloon girl, Penny Parker, snaps at them. She's immediately taken with MacGyver. The marshal and bartender, Wyatt, refuses to sell him milk but a local gambler, Jack Dalton, offers to buy a glass of sarsaparilla. MacGyver accepts as Milt Bozer grabs Penny. MacGyver intervenes and Milt offers to buy him a drink with a spider in it. If MacGyver refuses, Milt threatens to shoot him. MacGyver shows he isn't carrying but the Bozers aren't impressed. The veteran takes the glass, borrows Jack's cigar, and then throws the drink in Milt's face and the cigar down Wilt's pants. Dalton kicks Milt's gun away and Wyatt orders them out. Jack offers him a seat and realizes MacGyver wants to buy land. He has a deed for Big Springs Ranch ready and waiting, and admits he won it in a poker game. MacGyver bargains him down to $1,700 and Penny offers to go with them to see the ranch. As they leave, Wyatt and the other saloon girl, Pam, figure he won't last a week at the ranch.
MacGyver, Jack, and Penny arrive at Big Springs Ranch and discover Billy Colton and Lee Sing living there. They worked for the previous owner and everyone else left. Lee Sing says that they were scared but Jack quickly dismisses his concerns. They're interrupted when a gang of men rides up, including the Bozer brothers. The leader and local rancher, Pete Thornton, tells MacGyver to get off the land because he made a deal with the previous owner, Dave Nye, to have first purchase option. Jack points out that Nye lost it in a card game but Thornton isn't impressed. He needs the land for the water. Penny points out that MacGyver doesn't own a gun, and the Bozers admit they lied to their boss about MacGyver pulling a gun on them. Pete figures MacGyver will leave peacefully and accuses him of being gutless. When Pete tries to provoke a fight, MacGyver punches him and Billy Colton fires a shot before the Bozers can draw. Pete orders his men to drop their weapons but says that he'll be back. Once they're gone, MacGyver thanks Billy for his help
Realizing he needs help, Pete calls in a professional gunfighter: Murdoc. When the Bozers doubt if he's a gunslinger, Murdoc lightning-draws and shoots a sign down on them. Pete tells him that he only wants MacGyver removed from the land, not killed.
As MacGyver moves in, he talks to Billy and realizes that the boy is soon faking a Cajun accent. Billy finally admits that he was a slave in Alabama who worked a schoolteacher. He wrote fake papers so that he could get free and moved out West. When MacGyver wonders why he's continuing with the charade, Billy points out that the law might have changed, but people haven't. MacGyver insists that anybody can reinvent themselves.
In town, MacGyver is buying supplies when Jack and Penny tell him that a gunslinger is in town to go after him. MacGyver decides to talk to Pete and offer him access to water.
At the ranch, Murdoc rides out and demands to know where MacGyver is. When Billy tries to stop him, Murdoc draws and kills him. Riding up, MacGyver hears the gunshot. Murdoc tells Lee Sing to tell MacGyver that he dropped by and leaves. MacGyver rides up to discover his friend, dead.
In town, Pete demands to know why Murdoc killed Billy against his wishes. He pays Murdoc and calls him off but Murdoc refuses to ruin his reputation by failing to complete his mission. He tries to draw on Pete, who already has his gun out and is ready for him. Pete leaves and tells the Bozers that he doesn't want any deaths on his hands no matter how he was shamed.
MacGyver and Lee Sing are burying Billy as Pete rides up. He tries to apologize and says that he fired Murdoc. He agrees to back off from Big Springs Ranch and offers to pay any price MacGyver wants. MacGyver insists he wants to live on his land, not profit by it, and Pete agrees not to bother him. However, MacGyver offers to let Pete drill for water as long as he has enough for his needs. He's willing to abide by Pete's word, much to Pete's surprise. They agree to be partners and now there's only one thing left. MacGyver heads for town to bring Murdoc to justice and Pete insists on going with him.
Murdoc meets with the Bozers and demands to know where they stand. The brothers are eager to get revenge and Murdoc figures that MacGyver will be coming into town so all they have to do is wait.
As Pete and MacGyver ride into town, Jack and Penny try to get Marshall Wyatt to help. Wyatt quickly retires himself when Murdoc and the Bozers arrive. Jack backs down while Murdoc grabs Penny and tells Jack to inform MacGyver where he is. Jack rides out to warn MacGyver and Pete. In town, the Bozers set up an ambush. The three men ride in and Wilt fires early, shooting off Jack's hat. Jack, MacGyver, and Pete ride back out of town. Pete figures Murdoc is waiting to see if MacGyver can get past the Bozers. MacGyver goes after Murdoc while Jack and Pete get the drop on Wilt and use him as bait to lure Milt in and capture him as well.
MacGyver rides into town and spots Murdoc on a balcony ready to shoot. He takes to the roofs and uses a rope from a flagpole to drop down behind Murdoc. MacGyver attacks only to discover Murdoc has put his coat and hat on Penny and tied her hands to the railing. MacGyver cuts her free while Murdoc comes up behind him. Murdoc shoots MacGyver in chest and he tumbles through the railing and hits the ground below. Pete and Jack come running up and discover their friend, dead. As Penny arrives, MacGyver coughs and shows them that Murdoc hit the Swiss Army knife in his chest pocket, leaving a dent. Murdoc rides off and Pete vows that they'll get Murdoc one day...
MacGyver wakes up to find Pete there. Pete apologizes, admitting he was pushing too hard and trying to impress the board. MacGyver accepts his apology and tries to explain his dream. He looks around and spots an antique Swiss Army knife on the end table... with a dent left by a bullet.