"Extradition: British Columbia" is the first episode of season four. Shawn and Gus come across an elusive international art thief while vacationing in Canada.
Shawn and Gus are on the slopes on their ski vacation in Whistler, British Columbia, when Shawn spots wanted international art thief Pierre Despereaux. Despereaux is so good; he's never left enough evidence behind to be formally accused and so promptly gives Shawn and Gus the slip. Shawn goes to the Mounties for help, who need very little convincing of his psychic abilities. Deputy Commissioner Dykstra calls Lassiter to ask for Despereaux's files to be sent up, and Lassiter, who has spent over six years tracking the thief, insists on being part of the investigation. Lassiter and Juliet arrive in Canada just in time to meet Shawn and Gus at Despereaux's latest crime scene. The thief has stolen an antique necklace worth several million dollars. Shawn notices a spot on the wall where a painting used to be and assumes Despereaux stole that as well. The owner says he sold that painting two weeks ago. Lassiter sees all the telltale signs of Despereaux - no fingerprints, no alarms tripped, and a signature Merchanteuse Blonde cigarette burning in an ashtray - but not Despereaux himself. Shawn spots flowers in a vase inexplicably moving, like in a wind. But they are in a high-rise condo. Shawn tracks the source of the breeze to a window slightly cracked open. He pushes the window open and looks up to see a shoe disappearing onto the roof. Shawn rejoins the group and claims Despereaux is on the roof of the building. Lassiter is skeptical, but Shawn and Gus race up to catch the thief, who compliments them on a vast improvement on their skills from the horrendous skiing of the day before. Then he excuses himself, saying he's going back to his room - and jumps off the building. By the time Lassiter and the rest of the Mounties arrive, Despereaux has disappeared, leading everyone except true believer Corporal Mackintosh to doubt he was ever there at all.
A dejected Shawn and Gus go to a fancy restaurant for dinner. Gus wonders how they got a reservation since you have to make them months in advance, and Shawn only invited Gus on the trip on Friday. As they argue about those logistics, Shawn spots Despereaux across the room, waving them over. He tells them they are out of their league. It's impossible to catch him, which makes what would be an exciting life actually pedestrian. To make things interesting, Despereaux writes down everything he is going to do in town - grab a Manet, make them look foolish, and treat himself like a king. As Shawn and Gus are distracted by a flaming Baked Alaska, he disappears again. The guys then go to the Mounties, where Shawn 'divines' that Despereaux is going to steal a Manet that night. The only Manet in town is on the yacht of former billionaire now millionaire William Pulver. They all stake out the boat and pounce when they see a shadow moving on the docks, but it just turns out to be a surprised dockworker. From the dock, Shawn can see into the yacht and discovers that the Manet is gone. Despereaux somehow got it right under their noses.
Shawn and Gus regroup to discuss the case on a carriage ride where Gus finally realizes that Shawn booked the trip for Abigail, who had to cancel. Gus, angry at being an afterthought, throws Shawn out of the carriage and heads back to the hotel. On Shawn's way back through the park, he notices the distinctive roof of the hotel and remembers that it can be seen from the roof of the condo building. When Despereaux said he was going to his room, he was looking right at it. Despereaux is in the hotel. Knowing that Despereaux travels under aliases of famous artists, Shawn tracks down his room and starts searching it in the dark, when the lights come on revealing Despereaux is already there. He tells Shawn as he packs his suitcase that it was fun while it lasted but he's leaving town. But Shawn sees a receipt for dry cleaning that is due back in three days and realizes he's lying. Shawn says he knows when he's beat and promptly leaves. The next day, the cops get a tip that Despereaux is leaving town, but Shawn knows it's a diversion and insists Despereaux going to steal one more thing. The only person who believes Shawn in Mackintosh. Shawn remembers the last item on Despereaux's to do list will make him feel like a king, and Mackintosh helps figure out the target is the Monarch Butterfly Crown currently housed in a museum. Shawn realizes to beat Despereaux he has to steal the crown first, and with the help of Mackintosh, who helped install the security system, Shawn and Gus break in. But the alarm somehow trips anyway and they are soon surrounded by an armed Canadian SWAT team.
Henry flies up to bail Shawn and Gus out of jail. Shawn complains that they are dealing with the perfect crime, but Henry admonishes that there is no such thing as a perfect crime. They run into Mackintosh on the way out, who has just been fired. He tells them that the crown is missing but Shawn claims that's impossible. They were there when the museum closed and watched the owner leave. The only way Despereaux could have taken it is if he had it all along. Shawn then puts it all together and tracks Despereaux to a seaplane. Despereaux is so good because he never steals anything. The owners, who are in financial straits, hire him to make it look like a theft, as they sell their art on the black market and claim the insurance money. The cops arrive and Despereaux is arrested for insurance fraud. Lassiter gloats over finally capturing his prey after so many years only to realize Despereaux has no idea who he is. Shawn ends up taking Juliet on the date he intended to bring Abigail on.
The gallery for Extradition: British Columbia can be found here.