When the class bully disappears on a field trip to the River City Zoo, James Shoo, known as "Gum" and the other sixth-grade detectives are determined to find out what happened, and it is up to the reader to choose what direction their investigation will take.
Edward G. Garrison, better known as Egg, is pretty excited about the Science Club's field trip to the zoo where they will see a rare display of Island Foxes, an endangered species, but when the club arrives, they learn that the foxes have been nabbed!