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. A sinister force has decided to destroy the Lunch Club once and for all. This brand new villain makes Zaralgax seem downright cute (no easy feat — have you seen the guy?) and it’s up to Tia and Leo to save their legacy and get Mr. Peabody out of a particularly hairy situation.