One afternoon in Binghamton's office, The Captain vents his frustrations on Lieutenant Carpenter. It seems that there is a very rare variety of wine, made in the town of Voltafiore, and Binghamton would like to get his hands on a case of it, for General Bronson. Carpenter suggests asking Mayor Lugatto for help in finding some of the wine, and adds that Lugatto is waiting outside, at that very moment.
Binghamton suspects that Lugatto is not only waiting outside, but is listening to what they're saying, and it turns out that he's right. After Lugatto is admitted to the office, he knows, of course that Binghamton is looking for the Voltafiore Chianti, but quickly tells the Captain that there is none to be had. He goes on to explain that the Germans took all of the wine, during their last visit, and hid it in a secret location.
Binghamton thanks Lugatto for his cooperation, and, when Lugatto tries to bill The Captain for the information, Binghamton angrily throws him out. After the Mayor is out of sight, Binghamton states his firm intention to find that wine, no matter what it takes, and that he'll begin his search at McHale's camp.
Later, as Binghamton and Carpenter near the camp, McHale and the guys have plenty of advance warning of his approach, thanks to a periscope they've installed in the wine cellar. They quickly make their way to the main tent, and, when Binghamton arrives, the guys are all patiently listening to a map-reading lesson, from Parker.
Binghamton immediately makes known, the reason for his visit. After McHale and the guys truthfully deny any knowledge of any hidden wine, The Captain angrily makes it clear that – If they do have the wine, and don't turn it over to him – That he'll see to it that they're all court martialed for possession of war contraband. He then immediately orders them out on patrol, and McHale and the guys leave, immediately.
Later, as they head back to the base, they spot a German patrol boat, near shore. The enemy boat immediately opens fire on them, and, after McHale orders return fire, the German boat cranks up, and makes a run for it. Gruber suggests they give chase, but McHale won't allow it, for the 73 is very low on fuel. But, he suspects that the enemy boat may have been laying mines, so they ease in to take a closer look.
As they cruise slowly along the beach, Parker and the guys keep a careful watch over the side. Soon, Parker thinks he's spotted something, but loses his balance, and falls overboard. When McHale and the guys pull him back aboard, Parker brings up a heavy line. When they pull the line in, it has a package attached to it's other end, and, when they open it, they find that the package contains a case of the famous Voltafiore Chianti. Upon further investigation, they find that they have run across the Jerrys' hiding place of the stash of stolen wine.
They haul it all in, and transport it back to the wine cellar, where the guys bring in and stack up some 20 cases of the rare vino. Christy asks when they might turn their find over to Binghamton, and McHale answers that they don't, despite the Captain's threat of a court martial. He adds that he also has no intention of turning it over to Lugatto, for the Mayor would only sell it for a handsome profit. McHale says that the rightful owners of the wine, are the people of Voltafiore, and he states his intention to see that they get it back. He then adds that – Since the Germans don't know that their hiding place has been discovered – They will return the crates to the hiding place, with explosives in the bottles, rather than wine, so that the Jerrys get a big surprise, when they return to base with it.
Before McHale leaves, to go and procure explosives and fuses for the booby traps, he orders the guys to empty all the bottles into barrels, and makes it clear that they are not to touch a single drop of the vino. So, after McHale is out of sight, before they follow the Skipper's orders, the guys pour themselves a supply of the wine into their canteens, making sure that they don't "touch a single drop", while doing so.
Later, in the main tent, as McHale finishes the booby-trap, on the last wine bottle…
"All right, boys," says McHale, "This is the last of doctor McHale's super-charged Chianti. The wine with the guaranteed kick."
McHale orders Willy and Christy to take the last case back to it's watery hiding place, and, as they leave, he gives Parker a list of Voltafiore's leading citizens and asks that he go into town, to round them all up for their 'Wine Committee'.
Meanwhile, Lugatto and Baroni have made their way to the McHale compound. Lugatto suspects that McHale and the Crew have found the wine stash, and, when he finds an empty wine bottle lying nearby, his suspicions are confirmed. They then make their way to the beach, where they see Gruber and the rest of the Crew hiding the cases in their underwater hiding place, and Lugatto quickly decides to go straight to Binghamton, and demand that he turn the wine – Or the money for it – Over to him.
Later, in the cellar, Parker is checking over his list of townspeople, and, before leaving for town, grabs one of the canteens, for a refreshing drink of water, for the trip over, on the hot, dry day. After he takes a healthy swig…
"Wonder what well those guys got this out of?!" says Parker, with a cough.
Parker takes another swig of the powerful 'water', then another, and another, and, by the time he heads out for his trip to town, he's well on his way to being smashed.
Meanwhile, Lugatto and Baroni have gone to Binghamton's office. Carpenter tries to keep them from coming in, but is unsuccessful. Lugatto goes straight to Binghamton, with a report on what he and Baroni had witnessed, and demands 100,000 lira for the wine.
Binghamton is about to turn Lugatto down cold, but is interrupted by screeching tires, out in the town square. When they all go to the window, they see Parker, who is now pretty drunk, driving rapidly and recklessly around the town fountain, in a Navy jeep.
Binghamton, Carpenter, Lugatto, and Baroni rush outside, just in time to see Parker crash the jeep into a building. They rush over, where Lugatto soon finds that Parker is pretty well smashed. Lugatto presents Parker's condition, as well as the canteen of wine as proof that McHale has found the stash of Voltafiore Chianti, but Binghamton will have none of it. He tells Lugatto that Parker is suffering from battle fatigue, and that the liquid in his canteen is insect repellent.
Lugatto and Baroni have no choice but to retreat, and, after they're away, Binghamton talks the inebriated Parker into telling him where McHale's hiding place is. After Parker spills the beans, Binghamton and Carpenter leave, immediately.
Later, Binghamton and Carpenter float, in a rubber raft, over the spot where the wine is supposedly hidden. Binghamton orders Carpenter over the side, to look for the crates, and, he soon comes up with the news that he's found the stash of crates. But, little does The Captain know that Lugatto and Baroni have followed them to the hiding place. When Lugatto makes his presence known, he makes it clear that he and Binghamton are now partners in the operation.
Shortly later, in his office, Binghamton angrily charges McHale with the crime of possessing war contraband. McHale denies any knowledge of such contraband, but Binghamton soon produces evidence, in the form of one of the crates, recovered from the hiding place. Binghamton pulls one of the bottles out, and McHale nervously warns the Captain that the bottles are booby-trapped, and explains that they'd left the bottles for the Germans to find. But Binghamton doesn't buy it, and, when he tries to uncork the bottle, McHale rushes over, snatches the bottle from Binghamton's hand, and tosses it toward the corner of the office, then takes Binghamton and Lugatto to the deck, as the bottle explodes.
As they all come to their feet, dazed and dusty, but unhurt, Carpenter rushes in with the news that he's loaded one of the wine crates into the back of General Bronson's staff car. Binghamton and McHale rush to the window, to try to stop the General, but they're too late, and there is a tremendous explosion, outside.
Later, in the wine cellar, McHale is just finishing up the story. It seems that the General was unhurt, but was quite angry with Binghamton for the damage to his staff car. McHale then adds that the one thing he doesn't understand, is how Parker got so drunk. Parker – Lying nearby, trying to get over a hangover – Says that he doesn't understand it, either, and swears that he'd not had any wine. He then reaches for his canteen, for another swig of 'water', and comments on how "strong" the water is. He offers McHale a drink, and The Skipper takes him up on it. When he does, and realizes that it's wine, he at first gets pretty mad at the guys, for hoarding the wine, but quickly gives in, and invites everyone to join him, in a drink.