George Wendt has a chance here - finally - to move away from his lovable barfly "Norm" in CHEERS. Here he plays a hard working grasshopper type. He runs a horse farm, and has been grooming and training a potentially great horse. But he's stuck with a ne'er-do-well brother (Jeff Yagher)who is potentially going to wrecked all of Wendt's hopes by his gambling debts. Wendt kills this idiot, but now has to figure out how to avoid going to jail because of it. His brother's debts are owed to Jay Acovone (playing a bookie for the Mob). Wendt lures Acovone to his home to collect the debt, and shoots the bookie "in self defense". The idea is that Yagher was killed by the bookie as a message to Wendt to pay up or else.
Enter Colombo...and Peter Falk is soon beginning to spot all the apparent unnoticed minor details that Wendt overlooked (but which the surface incidents seem to cover pretty well). But Falk realizes he has competition. It seems mobsters have private lives too. Acovone was more than a Mob bookie: he was the close godson of local Mob capo Rod Steiger, and Steiger (who like most capos has a pretty shrewd head on his shoulders) realizes that Acovone had no hand in this crazy "message" murder if he was expecting to be paid.
What happens then is similar to an episode from the first decade of "Colombo" where Hector Elizondo was an Arab diplomat who killed Sal Mineo to hide and advance a conspiracy against his monarch, and Falk and the monarch end up putting Elizondo on the spot in a squeeze play. Here Steiger works with Falk in putting Wendt in a similar squeeze-play.
Falk and Steiger have nice moments together, including a moment of lunch when Falk suddenly realizes they are eating a specialty that he can't eat, but Steiger happens to like. But the best moment comes when Wendt sees his real moment of truth. Confronting Steiger and his army of goons at a small coffee shop, only Falk happens to be there. When Falk (playing his game on Wendt) sees that Steiger means to kill Wendt and anyone else who is "troublesome", he says finally, "My salary is not worth this!", and walks out. We know he's doing it to effectively scare Wendt, but boy is it funny to see his limit finally!