The detectives' classmate, Elena, has lost her show and tell object -- a gift from family in Puerto Rico. The detectives trace the object across campus and through countless hands, learning about the strong ties between family and place along the way. / Mulberry Springs' beloved Mockingbird Creek is overrun with litter and trash. Millie, Marta, and Mike take the case, but discover that while finding the source of the trash might be easy, cleaning up the creek is a different story.