Writer Robert W. Lenski did some research on this one, all about tricky pot smugglers. Around the time this episode was filmed, marijuana was being shipped into the US from Colombia at a rapid pace. The story broke everywhere!
Lenski changes the transportation a bit, having pot being flown in instead. In this case, a ranch employee spots the marijuana drop from the air and is chased down and killed. The catch here is that the man is using a CB radio, which connects Barnaby to the case. I agree with the last reviewer, this was at a time when CB radios were a national fad. Barnaby also gets to do his thing on the air.
The notable cast also brings this to life, especially an appearance by Andrew Robinson (as Sonny), best known as the insane killer in DIRTY HARRY. Pretty Devon Ericson plays Lois, who would appear several more times on the series. Annette O'Toole guest stars, later to play Martha Kent on SMALLVILLE.
Kenneth Tobey returns playing a sheriff. Yes, famous bit actor Bob Harks appears with Tobey. The man was everywhere on tv.
Interesting stuff, but the CB angle brings back lots of memories for all us kids back in the day. SEASON 5 EPISODE 6 remastered color CBS/Paramount dvd box set.