What happens when CatDog find themselves in a parallel universe? They meet a creature even stranger than they are! In this upside-down, topsy-turvy world, nothing is quite what it seems. For starters, everyone is too nice, especially the Greasers! To make matters worse, CatDog can't make "heads" or "tails" out of the creatures around them! Before long, CatDog wants to go back home. But will they be able to escape?