Oh, no! When mushroom boy Little Cap's pet slug, Gustav, goes missing, Little Cap is beside himself. How can he summon the courage to leave his cozy home to find him? But summon he does. There are many suspicious characters just outside his door and--gasp!--he has to talk to his neighbors, but Little Cap can't be stopped.

After much perilous searching--up sheer cliffs and into deep canyons and even stepping in something really, really gross--Little Cap finally finds his very best friend, and he's changed for the better along the way. Here is a story that celebrates friendship, perseverance, and bravery, told with Andrea Zuill's signature heart and humor.