LOGLINE: Gus has worked long and hard organizing their high school reunion, so when Shawn claims one of their fellow alumni has been murdered and his body has been hidden, Gus refuses to believe him. Shawn must now try to solve a case no one thinks exists before the reunion ends and the attendees escape back to their grown up lives.
SYNOPSIS: Gus is in charge of his and Shawn's high school reunion and he wants the night to go perfectly. He warns Shawn not to mess things up, then instructs him to go find more folding chairs. While Shawn heads to the cafeteria with Abigail, his high school crush, he sees, out the window behind her, someone fall to their death from the roof. But by the time they grab Gus and head outside, there is no sign of a body. Gus and Abigail don't believe anything happened, but Shawn claims the victim was wearing a letterman's jacket and, after they walk away, he spots part of a lapel pin in the grass.
Shawn follows Gus inside, insisting a crime has occurred. He calls Lassiter who, as it happens, is already there as the date of one of their fellow alumni, Mindy. He tells Shawn he can't do anything without a body, a murder weapon, a suspect or any evidence. Shawn describes the pin fragment he saw to Gus who tells him it's part of the State Champs pin the football team got their senior year. Shawn then remembers seeing that pin on their starting quarterback, Howie Tolkin, and claims he is the murder victim. But just then, he walks in alive and well with his wife Eileen.
Since Shawn just blew any credibility he had with Gus and Lassiter, he calls in Juliet for reinforcement. While waiting for her in the corridor, he notices someone has tampered with the trophy case dedicated to Howie's many football accomplishments. He and Juliet find Howie and Eileen to let them know about the vandalism, but Howie says he isn't bothered, claiming all of that is just history. He's moved on and is now running for the state assembly. Shawn and Juliet don't quite believe he's let go of the past so completely, but Shawn still can't prove anything. He needs to get onto the roof but Gus tells him the rest of the school is locked down tight. So Shawn calls Henry to ask him to find a box of high school mementos that's stored in the attic. Henry isn't familiar with the box, so he enlists Madeleine's help to find it. They both bring it to the reunion, embarrassing Shawn, who takes it from them and finds what he's looking for – a key ring containing all the keys to the school. He managed to join the custodial union when he was a student, he explains to Gus. He and Abigail then go to the roof to investigate, where he finds footprints that match the shoes of Howie and Eileen, finally giving him the identity of the killers.