The episode begins with Karen briefing the team about the crime boss, Max Rizzo. Rizzo’s accountant, Pollock, has fled the organization with Rizzo’s cash. This means that if they could get to Pollock before Rizzo does, they could get all evidence against Rizzo, which can put him behind bars. Lassie has taken a day off to do his wedding planning. He arrives at the precinct and distributes his wedding invitations. Gus tells Shawn that he will be going alone to the wedding, because Rachel has gone to London with Max to meet Max’s father.
Lassie tells Karen and Juliet that Marlowe’s friend from the prison, Big Wendy, is throwing a bachelorette party, and Marlowe would like it if Karen and Jules could attend. Lassie tells Shawn and Gus that he doesn’t want to have a bachelor party because his friend, Stumpy, is in Chicago and will not be able to attend. Shawn and Gus are disappointed. Later, the duo abducts Lassie and brings him to a party bus, which has disco lights and music. Stumpy, Woody, and Henry are also there. Lassie is glad to see his best friend. They decide to start the party. Lassie doesn’t want any crazy stuff because he is getting married tomorrow. Stumpy gets some beer and Henry warns them not to mess up the bus because the contract is in his name. The guys arrive at a casino, and Stumpy takes $300 from Lassie to hook up with a hooker.
Gus and Shawn think that Stumpy is an idiot, but they are also happy to see Lassie cut loose. Lassie and Gus go to the slot machines. Shawn sees Pollock enter the casino. The bachelorette party is in full swing and the girls are drunk. Wendy has called a male stripper and it turns out to be Officer Buzz McNab. At the casino, Gus is getting all worked up because Rachael hasn’t called him yet, and Shawn has managed to plant the seed of doubt in Gus’s head. Shawn tells Gus that Pollock is at the casino. They need to alert the police and get Pollock out of there, or else this party will turn into a work trip. At that moment, Lassie arrives with Pollock. It seems he has already found him. They decide to take Pollock back to the precinct.
Pollock tells Lassie that he, too, wants to put Rizzo behind bars so that he doesn’t kill him. He says that the flash drive containing information on Rizzo’s taxes are at his place, which is nearby. They go to Pollock’s house and Pollock goes in to get the flash drive. At that moment, he hears some noises and finds out that Rizzo’s men are there too, but in another room. Pollock tells Lassie and his friends to run. They all get into the bus and drive away. Rizzo’s men tell Rizzo that Lassie got to Pollock before them and also that Lassie is getting married.
At the bachelorette party, Juliet talks to Buzz, who is still dressed as a male stripper. He had told the department that he is working as a security guard at the casino. Buzz begs Juliet not to report him. Karen has passed out, due to excessive drinking, and Jules tells Buzz to leave. She joins Marlowe at the table. Marlowe tells her that she is not sure if she is ready for marriage. She feels that everything is happening too fast. Later, the girls learn that Marlowe is missing. Lassie and his gang head back to their hotel, with Pollock, when Rizzo calls. He tells Lassie that he has Marlowe with him, and Rizzo offers to trade Marlowe for Pollock. In the hotel room, Lassie finally decides to hand over Pollock to Rizzo, so that Marlowe will be released. Karen is drunk and is sort of unaware of what is happening. They decide that they can brief her about it later.
Wendy and Woody were supposed to keep an eye on Pollock, but the two of them end up having sex and Pollock manages to escape. Shawn has an idea. Lassie’s team and Rizzo’s team arrive at the decided spot and the swap takes place but, before they leave, both parties realize that they have been tricked. The guy who was handed to Rizzo as Pollock is actually Henry, whose head was covered with a cloth bag. Lassie finds out that the girl handed over to him is not Marlowe. He is furious and Rizzo tells him that Marlowe escaped. Lassie tells Rizzo that Pollock, too, escaped under their watch. Later, the team checks the room Marlowe was held in.
Lassie finds it impossible that Marlowe jumped out of the window. Shawn recalls the way Rizzo described Marlowe’s escape and figures out that Marlowe went down the garbage shoot. They find Marlowe. Lassie thanks Shawn. They have less than two hours for the wedding and Juliet takes Marlowe with her. The guys get dressed in their suits. Woody ends up wearing swimming trunks, because it seems that Lassie wasn’t very specific when he said “suit up”. Shawn notices the Aqua Verde Theater and remembers taking a receipt from Pollock’s place, because Shawn is a Michael Damien fan. Once again, Shawn is right and they find Pollock. Rizzo’s men are keeping a watch on Lassie and the team.
They inform Rizzo that the team found Pollock. Next, Juliet tells Marlowe that Lassie loves her a lot and that she has never seen him this happy. Marlowe tells her that she is now confident that she wants to marry Lassie. In the bus, Lassie is writing his vows. Pollock is surprised that a stupid guy like Stumpy is Lassie’s best friend and best man. Lassie says that Stumpy is not his best friend. He says that he was embarrassed about the fact that he had nobody who he could invite to the party or the wedding. He knew Stumpy from high school and his name was the first to cross his mind. Everyone is glad that Stumpy doesn’t mean anything to Lassie. Next, at the wedding venue, Lassie learns that the guy who was supposed to marry them is nowhere to be found. Pollock tells him that he is a licensed Justice of the Peace and, therefore, he can conduct the wedding. Lassie is glad.
Karen cuffs her leg to Wendy’s so that she doesn’t slip and drink, thereby violating the parole. She had already done it for the bachelorette party. Pollock is still cuffed. Marlowe arrives but, before she can walk down the aisle, Rizzo and his men arrive and Lassie asks everyone to duck. It is a cop wedding and, obviously, everyone has a gun. A gun fight ensues. Rizzo is arrested. They continue with the wedding, and Lassie and Marlowe finally get married. At the reception, Gus receives a call from Rachael. He is happy. Juliet is freezing and Shawn makes her wear his coat and goes to get some drinks. Henry gives Shawn some fatherly advice.
Juliet questions Shawn about his psychic visions. She reminds him that he said that he had a “vision” about Marlowe being covered in garbage and Pollock being at the theater. She pulls out the receipt from his coat. She knows that Shawn already knew that Pollock would be in the theater. She asks him whether the whole “psychic” thing is a lie. Shawn doesn’t want to answer that. Juliet throws the drink at him and storms out of the hall. The episode ends.