This Bonanza episode is one of two that Ed Begley guest starred in in two separate roles. This film has Begley and his sons who run mule train freight packing outfit helping Lorne Greene deliver a cargo of nitroglycerin for the miners. It's rugged high country they're traveling in and Ben Cartwright is joined by Hoss and Little Joe halfway through the trip.
Begley has some issues with his two sons. There's the favored older son Tom Simcox and the younger son who can never please Begley. Begley has some deep psychological problems with Evans who all he wants to do is win his father's favor.
This episode is one of the few, maybe the only one that ever referenced Adam Cartwright after Pernell Roberts left the series. It was Adam in a letter to his father extolling the virtues of nitro and how helpful it will be to the mines and the general prosperity of the area. He also quite explicitly tells of the dangers and volatility of the stuff and that knowledge helps Lorne Greene defuse a bad situation.
Nice performances by guest stars Begley, Simcox, and Evans.