L'il Mo is a retained baby molar who never becomes loose because his permanent replacement tooth never grows beneath him. Instead of falling out and going with Tooth Fairy, L'il Mo will have to live with all the big new teeth that have moved into his neighborhood! At first he doesn't want to be different from his baby tooth buddies, but MolarTron & Friends help L'il Mo see that there are many advantages to being a unique and interesting individual.