Fishtronaut, Marina, and Zeek investigate a series of unusual events in the Park. They discover that Doctor Green had gone to the city and left Billy and Mac in charge of a few tasks. The boys, however, forgot about their responsibilities. With everyone's help, they're able to get the Park back in order!
Fishtronaut, Zeek, and Marina are enjoying some of the Park's fresh fruit when one of Marina's teeth fall out. She looks everywhere for the tooth, wanting to put it under her pillow later for the Tooth Fairy, while Zeek wonders if there's such a thing as a Tooth Monkey-Fairy. A POP arrives at that very moment, bringing them a cane and an old-fashioned nutcracker. Zeek carries on the search for the tooth, while Fishtronaut and Marina consult Happy Plumb about the clues. On this investigation, they learn about the different natural cycles in animals and humans.