Magical fanboy imps Bat-Mite and Scooby-Mite are back-and they've brought along a host of Batmen and Scooby-Doos! But when the mites conjure up the ultimate trans-dimensional menace for our heroes to battle, will even a League of Batmen and Society of Scoobies be enough to save their infinite Earths? Plus, can they unravel the mystery behind the shadowy figure known only as...Scrappy-Doo?