The boys go into research mode at a local diner, where Sam orders a health shake, and I share Dean’s disgust as he drinks it. As they uncover whose likely haunting Donna’s house, they’re unaware of Gary the counter boy stalker watching them. They split up to search for more information on the house. Sam returns to the motel, someone tranqs him. He awakes in the counter boy’s uniform, and gets picked up by a police man calling him Gary. The officer takes him home.
Back at the motel, Dean finds Gary, in Sam’s body, checking himself out. Gary tells him that the maid saw their guns, and both agree they have to leave. Gary ditches all the cell phones, and as they leave Gary asks to drive, Dean reluctantly agrees to let him behind the wheel of his baby. Dean should follow his gut instinct, because shortly after Gary hits a sign, and dean gets back into the driver’s seat where he belongs.
Back at Gary’s, Sam gets called down for breakfast. Gary’s stepfather, Leonard, starts laying into him about his future and plans for MIT. Sam is angered by his pushing, but plays along. Sam asks if he’s been doing anything odd lately, which leads to Leonard wondering if he’s on drugs. Sam eats a piece of wheat bread, only to discover that Gary is allergic to gluten, after throwing up, Gary’s sister Sydney tells him to stop being stupid, and asking about the book he snuck into the house.
Gary meanwhile tries to find out what they’re investigating, once he learns its about stopping Maggie Briggs’ ghost he tells Dean Maggie’s horrific history. As they drive to the house, Gary tells Dean to turn the music up, raising all kinds of red flags.
Sam goes to high school, and tries to blend in. Gary’s friends, Trevor and Nora, ask what happened, and Sam tries to cover. He searches Gary’s locker and finds a dark tome.
At Donna’s house Gary and Dean search the basement, finding Maggie’s bones. Gary picks up a shotgun, intent on shooting Dean when the ghost strikes, slamming into him. Dean tries to help, drawing the ghost’s attention and Gary salts and burns her bones.
Sam plays hooky, only to be caught by Gary’s friends, and winds up getting tranqed for the second time.
Meanwhile Gary and Dean are celebrating, Dean orders a bacon cheeseburger, and Gary orders the same. Dean jokes that its like he’s a different person, that he’s not usually so cheerful. Gary brushes it off saying its nice to escape from a life where his future is set. After a couple of drinks Dean relaxes, until Gary leaves with Crystal.
Sam awakes tied up at Trevor’s house. Trevor calls Gary. Gary tells them he hasn’t killed Dean yet, as Trevor warns that Sam is in his body. Gary shrugs it off, no one will believe him. Trevor urges him to hurry up and kill Dean, ending their conversation. He tells Nora, Gary isn’t going to go through with the plan. They tell Sam that there’s a demon bounty on Dean’s head, as Trevor summons a demon to kill Dean.
Gary tries to kill Dean, but he’s ready for him, and disarms him.