Our story opens with our heroes prowling the street in fedora's and trenchcoats searching for an all-night pizzeria when they come across a sumo wrestler, named Tattoo, breaking into a pet shop and saying something about looking "for home." But when the TMNT try to subdue the gigantic wrestler, he electrocutes himself and transforms into a hamster and quickly walks into a cage with other hamsters. Donatello deducts that this could be the work of Shredder and Krang... that the deadly duo are once again messing around with the Mutagen.