Shawn and Gus are being followed by the worst P.I. ever. Shawn's actually taken pictures of himself being surveilled over the last few days. Finally they confront their stalker, who lights a cigarette and confesses that he was hired by Gus' wife. Gus admits to a shocked Shawn that he met Mira Gaffney when he was in Mexico on Spring Break in 1997. She was crazy and could get him to do things no one else could, like skydiving and getting married on a drunken binge. Shawn insists on coming with Gus to meet her and Gus agrees, making Shawn promise not to let him get sucked back into Hurricane Mira again.
Meanwhile at the police station, Lassiter finds out that Juliet scored higher than him on the detective's exam. She never told him because she knows how he hates to lose. He claims he's fine with it.
Shawn and Gus meet Mira at her family's winery, one of three her family owns, it turns out. Gus immediately falls back under her spell. She tells them she's getting married, to a Swede named Jann, who she met at a wine convention. Some paperwork on her and Gus' annulment got messed up and she needs him to sign a few documents before she gets married the next day. She wanted the wedding to be at the winery but the only thing Jann wanted was for it to be on the beach. She then invites them to the wedding but when they show up they discover that Jann is missing. Mira is devastated but her father is not surprised. Jann hasn't attended a single pre-wedding event, but Mira insists he was called into work those days. Gus is moved by Mira's tears, and offers to help find Jann.
Back at the police station, Lassiter is having a hard time coming in second to Juliet and proposes a challenge. Juliet is working a case on a missing refrigeration truck from a seafood warehouse. Whoever finds the truck first, is the better detective. She accepts
At the winery, while Mira shows Shawn and Gus pictures of her and Jann, Shawn sees an outdated prescription bottle in her purse. Gus wants to be alone with Mira, and insists Shawn go talk to her parents. On the way, he notices some yellow paint on one of the walls. Mrs. Gaffney tells Shawn she didn't know that much about Jann and he immediately deduces that she has never met him. They go to the Gaffney's private cellar where the wine is worth over $1 million. Mr. Gaffney arrives and, from his shipping forms and blueprints, Shawn "divines" that they will be moving their valuable collection to a new winery in Napa, where it can be displayed.
Back at the Psych office, Shawn tells Gus that he thinks Mira made Jann up and asks Gus about the pill bottle he saw. Gus tells him that medication is for anti-anxiety but can also be used to treat psychosis. Shawn and Gus meet the Gaffneys at the police station and just as he tells everyone Jann doesn't exist, Jann himself shows up looking for Mira. He explains he was called away on business before the wedding and couldn't make it back on time. Now, technically their case is solved but Shawn knows there's something weird going on and goes to Jann's hotel to further investigate. However, Mira is there alone and Shawn confronts her on the photos he knows are fake. She confesses that she only recently met Jann, but after her whirlwind wedding to Gus, she didn't want her parents to think she was jumping into marriage again. So Jann suggested they fake photos to make her parents think they were together longer. Shawn and Gus track down Jann at the golf course and observe him having a clandestine argument with the private eye that was following them earlier, Mace Rhoden. They confront Jann who tells them that his fight with Rhoden was related to expenses from tracking Gus down. He was the one that hired the P.I. Also, Shawn gets him to confess that he wasn't away on business when he missed the wedding. He was in another relationship before he met Mira and he was putting an end to it for good. He knows Mira is the best thing that's ever happened to him and he doesn't want to lose that.
Lassiter and Juliet take turns interrogating an informant for information on the refrigeration truck. They compete to see who can get the information first. The informant ends up telling both of them that no one is trying to sell the truck, so the thief must need to use it for something. McNab tells them that the Chief needs them, and they run out to meet Shawn and Gus at Jann's hotel - only to find him murdered in his room. Shawn suspects Mace Rhoden is responsible and wants to talk to the police, but Gus knows Mira will be upset and goes to the winery to comfort her. When he gets there, he and Mira discover signs of a break in. Someone is trying to steal the private wine collection. And that someone pulls a gun on them.
At the police station, Shawn is about to tell the cops about his theory on the murder when McNab comes in with fingerprint results off the gold lighter that was left at the scene of the refrigeration truck robbery. They belong to a man with several aliases, one being, Shawn guesses, Mace Rhoden. Shawn remembers Mace had a gold lighter and confirms the stolen truck was yellow. Gus is in danger and as they race to the winery, Shawn tells Lassiter and Juliet that he was right about Jann not existing. He's a con man working with Rhoden who was pulling a long con on Mira. They needed a way to get the whole family out of the winery so they could steal the expensive wines and needed the refrigeration truck to transport it. But Jann really fell for Mira and backed out on the deal. Mace killed him and is at the winery now stealing the wine before it gets transported to Napa the next day. When they heroically arrive at the winery, they find Mace already unconscious on the floor and Gus and Mira safe and sound. Shawn gives an elaborate explanation of how Gus saved the day, impressing both the cops and the Gaffneys. In reality, Mace's lighter set the sprinklers off and he slipped and knocked himself out. Gus then accidentally knocked Mira over on his way to escape, so she doesn't remember any of it. With the case solved and everyone safe, there's only one problem left - an appreciative Hurricane Mira back in Gus' life.