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.