In the Caribbean country of Santo Thomas, General Kristoff, a guerilla leader, smashes into the bar of the Loa Bay Hotel with his rebel soldiers. The owner, Ivor Phillips, is calmly waiting for him. When Kristoff calls his scum, Phillips points out that Kristoff came to him and his partners, an international cartel that want to finance his revolution. The owner shows Kristoff the safe he has hidden behind the bar and assures the general that it's impenetrable, and explains that once Kristoff signs the agreement between them, it will be held in the safe until a courier can move it to their bank in Switzerland. Kristoff isn't convinced about the security measures but Phillips assures him that no one in the world could open the safe except him.
Al arrives and finds a party going on with Noah as the host. Noah talks to him privately and explains that he'll be leaving for Santo Thomas that night. El Presidente, nicknamed "The Undertaker," is an aging dictator and his replacement is in favor of democratic reforms. If Kristoff takes over then future relations with the U.S. and Santo Thomas are doomed. The SIA knows about Phillips and his cartel, and is aware that they've discovered bauxite deposits in Santo Thomas. Since El Presidente has refused to deal with them, the cartel is financing Kristoff in return for the mining rights. Phillips' hotel is in an isolated part of the island country and will serve as a meeting place when Phillips and his partners sign the agreement with Kristoff. The SIA wants Al to get the agreement so they can use the threat of public revelation to force the cartel to break their deal with Kristoff.
When Al points out that he must not expect him to return because he's throwing him a party, Noah explains that everyone outside is a SIA agent except for the bartender and mixologist, Englishman Cormack Shannon. Phillips has hired Shannon to provide drinks for his guests, and the SIA wants Al to take his place. As they watch Shannon make a Volcano martini that ignites from the heat of human contact, Al points out that he doesn't know anything about mixology. Noah tells him that Shannon is publishing a book and helpfully tells Al where he can steal the manuscript.
After he steals Shannon's manuscript, Al soon arrives at the Loa Bay Hotel, posing as Shannon. Phillips' beautiful daughter, Linda, is on hand. She greets Al and points out the case of poisonous snakes that her father keeps on display, and then takes him to the bar to go to work. A local band is performing and the lead singer watches Al as the guests ask him to make a Volcano martini. As Phillips comes in, Al opens a case of pre-made ingredients and makes the drink from Shannon's notes. It fails to ignite when Linda takes it and Al quickly blames the failure on improperly aged gin. Phillips is skeptical but Al pours the drink down the sink and watches as Phillips and the cartel members go into the neighboring conference room. An angry Linda warns Al that her father isn't happy and walks away.
Once she's alone with Al, the lead singer, Jasmin, comes over and introduces herself. Al grabs a tray and says that he's going into the conference room to serve drinks. When Jasmin warns against it, Al says that he's come a long way to do what he does best.
In the conference room, Phillips meets with the other four members—Machado, Kruger, Vogel, and Boileau--and tells them that once they've made the deal with Kristoff, there's no turning back. When Vogel wonders if they can trust Kristoff, the general storms in with his men. Phillips introduces his fellow cartel members but Kristoff says that as the one who is doing the fighting, he'll choose who to trust. As Phillips invites him to sign, Al comes in with drinks. The owner warns that Al has now disappointed him twice, but Al insists on serving each drink personally. He knows what everyone, even Kristoff, drinks and has made them to their precise specifications. The cartel members congratulate Phillips on his choice of mixologist while Al quickly takes in the room, noticing an air vent at floor level.
Once everyone signs the agreement, Al leaves the room and slips into the adjoining cellar to trace the air vent. He finds Jasmin there, listening in on the meeting as Phillips places the papers in the safe and then hands out six electronic keys to Kristoff and the other four cartel members. Phillips explains that all six keys in conjunction must be used to open the safe. Until the Swiss courier arrives the next day, each man must keep his key safe. Al interrupts Jasmin and she quickly realizes he's more than a mixologist. She suggests that they work together, threatening to reveal him if he doesn't, and Al cheerfully accepts her offer.
As Jasmin and Al go back upstairs to the main bar room, Phillips closes the safe behind the bar and hands out the keys. He complains that Al has an unfortunate habit of showing up why he isn't wanted, but Al hints that he was in the cellar with Jasmin for romantic purposes. Kristoff is smitten with Jasmin and promises to make her a national landmark once he takes over. Once the general leaves with his key, Phillips tells Al to forget he saw the safe and Jasmin escorts her new partner out. The cartel members warn Phillips that they can't trust Kristoff, but he isn't concerned and gives them their keys.
Later, Al searches Vogel's room first and removes the key from the sleeping man's grasp. He meets Jasmin near the snake case and shows her the stolen key, and tells her that they can't be duplicated so they need to steal the other five. When Jasmin worries that it's impossible, Al assures her that amateurs always hide items in predictable bases. They watch the nearby Kruger fumble for his pocket watch and Al figures that the man has the key hidden there.
Later, Vogel reports that his key is missing. Kristoff is upset and wants to have Vogel killed for his failure, but Phillips assures him that one key is useless. He also points out that Vogel is supplying Kristoff with armored columns and is too valuable to kill. Kristoff backs off for the moment but then orders his men to search everyone. When the cartel men object, Kristoff ignores them. He calls over Al and Jasmin and has them searched but finds nothing. The general threatens to kill all of them if the key isn't found by the time the courier arrives and walks away. Al offers the cartel members drinks and goes the outside bar with Jasmin, who wonders where he hid the key. The thief tells her that he slipped the key onto her without her knowledge... somewhere intimate where the guards wouldn't search.
Later, the cartel members hold a party on the hotel lawn and Jasmin's band plays while Al mixes drinks. Phillips and Machado talk privately and wonder if Boileau or Kruger stole Vogel's key as part of a double-cross. The others come over and wonder if Kristoff took the key so he could obtain the document and blackmail them into providing their support free of charge. Phillips tells them to worry about their own keys and make sure that they're safe. Kristoff brings his soldiers in to feed at the banquet tables, ignoring Phillips' protests. As they watch, Jasmin tells Al that she'll get the key from where Kristoff has it around his neck, leaving the thief to get the other four. Al has already pinpointed the location of three of the keys but hasn't been able to find Phillips'. The only place left to search is Linda's room and Al tells Jasmin to meet him at 4 a.m. once she steals the key from Kristoff.
That night, Al delivers nightcaps to the cartel members. They soon pass out from the drugged drinks. Meanwhile, Jasmin goes to see Kristoff where he's camped out with his men in the lounge. She asks to see Kristoff alone in his bedroom and he eagerly accepts while his men cheer him on.
Al goes to Linda's room with drinks. While she gets out of the shower, he searches the room and finds the key in her cold cream jar. Al quickly pockets it as Linda comes out in a negligee, kisses him, and assures him that he won't need drinks to seduce her.
At 2:30 a.m., Al leaves the sleeping Linda and steals the keys from the other cartel members. At 4 a.m. Jasmin slips out of Kristoff's room and meets Al at the bar. They use the six keys to open the safe and get the agreement, but Machado emerges from the wine cellar, wielding a gun. He tells Al that he didn't drink the drugged nightcap because he suspected something was going on. Al figures he's El Presidente's agent, but Jasmin says that he isn't and the thief realizes that she's the dictator's agent. Jasmin admits that it's true but insists that she only supports him because she knows he will soon die and Kristoff is the worst of two evils.
Machado tells them that he's not rich like the other cartel members and that he's looking out for himself. Unseen, Kristoff comes in behind Machado as the man says that Kristoff will let the others live once the agreement goes missing. The general disarms Machado, who claims that he caught Al and Jasmin stealing the agreement. When Machado urges Kristoff to shoot them, the general agrees that thieves should be shot... and then kills Machado.
As Kristoff prepares to kill Al and Jasmin, Phillips arrives and demands to know what is going on. Al claims that Machado blackmailed Jasmin into stealing the keys by threatening to expose her true loyalties to El Presidente. When Phillips wonders why she turned against Machado, Al says that she fell in love with Kristoff. Phillips laughs skeptically and Kristoff takes offense, asking why the idea is so ludicrous. The cartel member tries to apology and salvage their partnership, but Kristoff says he prefers Al's lies to Phillips' truths. Taking command, Kristoff takes the agreement and puts the briefcase holding the agreement into the snake case with three guards standing watch. The general tells Al and Jasmin that he hasn't decided what to do with them yet and orders them to their bedrooms while he gives the matter some thought.
Once the others leave, Jasmine complains that Al betrayed her, but he points out that at least she's alive. He asks what El Presidente plans to do and Jasmin explains that the dictator's men are watching for the courier and will follow him to the hotel to kill Kristoff. With an hour until the courier arrives, Al takes out a reel of fishing line and climbs up through the closet into the ceiling crawlspace. Jasmin follows him as Al goes to the ceiling above the snake case. He drills a hole through and then lowers the hook on the fishing line down to the case. Once he hooks it, Al waits until the soldiers look away and then lifts the briefcase up and swings it out the window.
When the courier arrives at 9, Al and Jasmin slip outside and recover the briefcase. Once the courier goes inside, they knock out his driver and leave in the limo. Inside, Phillips and Kristoff realize that the case is gone. El Presidente's soldiers surround the hotel and order them to surrender, but Kristoff refuses. When Phillips derides him as a fool, Kristoff has enough and shoots him dead. The army respond to the shot by opening fire, killing Kristoff, his men, and the other cartel members.
Once they're clear of the hotel, Al pulls over and asks Jasmin what she personally gets out of the mission. Jasmin doesn't have an answer and Al introduces himself with his real name. He suggests that they find somewhere private for a more intimate conversation, but Jasmin tells him that he's no Kristoff. Realizing that he was right earlier and she did fall in love for Kristoff, Al concedes that anyone who hates El Presidente can't be all bad and offers to drive her home.