Tia and Leo narrowly escaped the clutches of the awful alien Zaralgax, only to face the terror of the ... Pleasantwood Elementary Science Fair? Thanks to Mr. Peabody, their exhibit is about stamps -- a subject so terrifyingly boring they might not survive until the next Lunch Club meet-up. Against all odds, they do, just in time to plan their costumes for the big Halloween party. But when a werewolf who looks oddly familiar makes off with the school principal, Tia and Leo realize their supernatural problems are far from over.