Chester's countrified uncle visits Chester in Dodge. Trouble is Chester has misled his uncle by mail into thinking he's the marshal in Dodge instead of just the deputy. Now Matt's got a problem since he doesn't want to embarrass his loyal assistant.
The first 5-minutes of byplay is hilariously played by Matt, Doc, Chester and Uncle Wesley (the familiar Dabbs Greer), showing again the marvelous chemistry between three of the cast principals. I doubt that whoever put together the cast principals, including Kitty, foresaw them gelling the way they did. It's a really underrated part of the series' enduring success.
Anyway, I would have liked the episode much better had the writers not dug a hole for themselves in a way that requires proving Chester's actual prowess, which then forces a highly improbable narrative twist. Nonetheless, the byplay is worth catching up with.