Marshal Burl Masters returns to the Arizona town where he lives to find a gang known as the Apache Brothers has destroyed the place. The people of the town blame Masters for leaving them vulnerable to attack. To make matters worse, Masters' romantic interest, a woman named Willa, left with the gang.
Six months later, Masters finally tracks the Apache Brothers to Dodge City. Shortly after arriving at the Long Branch Saloon, one of the gang walks in, sees Masters, and draws his gun. Masters is faster, and draws his gun and kills the man. We soon learn this marks the third member of the gang Masters has killed. Masters is intent on killing all of the gang, including their leader, a man named Cheeno.
Matt Dillon and Masters are old friends, hence the title of the episode. Masters becomes acquainted with Miss Kitty, Doc Adams, and Festus Haggen as he and Matt reminisce about old times. The Marshal quickly becomes concerned at Masters' presence in Dodge and his plans for going after the remaining gang members.
The Apache Brothers are planning to rob the Dodge City bank. They hatch a plan to lure the Marshal and a posse away from Dodge.
All of these events establish a situation where Masters is doggedly pursuing the gang, while Marshal Dillon is trying to protect Dodge City, and keep Masters from fulfilling his lust for vengeance.
Fritz Weaver, who seemingly had a part in every television show from the late 1950s to 2000, makes his only Gunsmoke appearance as Marshal Burl Masters. His performance here as the driven, tortured Masters stands out.
Over 20 seasons, there are bound to be some themes repeated, and this is the case with this story. The final episode of Season 14 is titled "Exodus 21:22," and it has a lot in common with this story, although many of the specifics are different.