Columbo takes Adrian to a fancy restaurant as an apology for hounding him so much. During the meal Columbo orders all of the wine to show Adrian how much he has learned. For dessert he orders a super fancy/rare port which Adrian gets all excited about. But when he tastes it he explodes in a rage because the wine has been spoiled. As they leave the restaurant Columbo mentions how last week there had been a terrible heat wave.

The next day Columbo visits Adrian and finds him distraught and emptying out/destroying his entire wine collection. Adrian has now realized that the port wine in the restaurant was probably from his own wine cellar (Columbo confesses to having swiped it when he asked to be "locked" in the wine cellar') After Adrian smashed Rick in the head he had left him to suffocate in the wine cellar and he had unplugged the wine cellar's climate control, but with that unexpected heat Adrian's entire wine collection had been ruined!

With his life's collection of rare wine destroyed, his secretary blackmailing him and Columbo closing in, Adrian confesses and mentions that one way or the other he would be imprisoned: Either with his blackmailing secretary or arrested for murder. He prefers to be arrested. Columbo rides him to the station and shares a last bottle of wine that he had picked up for the occasion. Though the two men are from different worlds, tastes and on the different side of the law, they have a mutual respect and admiration for each other's talents.

Thank you very much, Pete. Now my Sunday evening has closure.

Well-done, Pete!

The ending seems to confuse a lot of people -- we've seen lots of questions like "How does the spoiled wine prove anything?" -- so I'll add a couple of things about that clue.

The spoiled wine may not "prove" that Adrian was the murderer, but it does tend to show that the cellar got overheated, as itf the climate control had been off during the heat wave (while Adrian was out of town). The key thing about that, is that the cellar is air-tight, so when the AC was off, the cellar became a good place to suffocate. Columbo had intuited this very early, comparing the wine cellar to the suffocation-chamber in Poe's story ("The Cask of Amontillado"). And, due to other little clues, he was already looking for a likely place -- NOT the ocean -- for the victim to have died from lack of air.

But as Pete summed-up, the point is not that the wine is, um, air-tight proof -- it is the final leverage for Columbo to push Adrian, who already felt trapped, into confessing.

As much as anything else, it was Adrian's dread of marriage that did him in -- but Columbo also knew this about Adrian, and twisted the screw by telling him how important the secretary's alibi was in exonerating him. So this is another case where Columbo solves the murder using his gift of insight into the suspect's psychology.

A true classic episode. And whenever I don't like a certain wine I look at my wife (not in public of course, lol) and say: "Everything is wrong! How could you serve me this LIQUID FILTH!

This is one of my favorite episodes, and I appreciate the discussion on this thread. The question I still have is, "What did Columbo do to Adrian that made him so apologetic on his call from the secretary's house?" Colubo tells Adrian that he was happy that Adrian did not report him - but to me Columbo did not badger Adrian at all. I keep thinking that for some reason my DVD does not contain some important scenes. I know that Columbo wanted to get Adrian to the restaurant to complete his plan - but he might have just invited him without the apology.