Jason and Brett Bates have just accompanied thei divorcedr oceanographer mother to the most remote but advanced underwater facility in the world: O.R.C.A., a veritable city-state, where hundreds of people live and work. But for two young adolescents, this is hardly the adventure of a lifetime. Until the day they meet Neri. A girl swimming in the middle of the ocean, with no visible means of survival. She is accompanied by a large humpback whale, who she calls Charlie. The boys eventually track Neri to the remote island where she lives, and form a close friendship. They learn that Neri has no idea of her past or explanation for her unique abilities (breathing underwater and a telepathic link to Charlie). As this series progresses, more and more is uncovered about Neri's origins, but this only leads to more danger...