Livingstone and Reenie are struck by THE GLUMS, a rare Animalian version of what we call "the blues." If not treated properly, "the Glums" can are irreversible! There is only one cure for "the Glums" -- a good long laugh. But there's one problem in achieving that laughter: those affected with the Glums don't find anything the least bit funny! Alex, Zoe, G'Bubu and Iggy, in order to save Livingstone and Reenie, must crisscross the kingdom and search everywhere and everyone for... ...The funniest joke in Animalia!