The Devil's Spawn

Ambushed and shot by an escaped prisoner, Bronco is saved by a rancher called Pete, but finds himself drawn into the rancher's feud with a nearby family. Bronco is there to arrest the escaped prisoner -Jeb- who is the brother of Pete who helped him, and allows him to stay even when he learns why Bronco is there. To catch his brother who is on hiding. Truth is that Rob doesn't like Jeb's outlaw ways and the feud is due to him robbing the bank which contained the opposition's money.

Pete has another reason of not being happy about his brother returning ... he's the father of one of his son's. Either Bart or Bud. Bart is a hothead and a troublemaker so it looks likely he's the son of Jeb.

And the viewers don't learn this until the end. Pete, played by Mike Keene, refuses to tell Ray Teal's Jeb who is his son. It's a well-acted and thoughtful episode that has sufficient conflict and plot twists to keep one interested.