t’s a fantasy novel about a boy named Luke who meets a mermaid-like creature in an aquarium where he is working nights. The creature, called Urhoa, reveals that his grandfather owed her a favor, and since he never fulfilled it, she is now calling upon Luke to finish it. Luke is struggling–he was a passenger in a car accident that killed the other driver and put his best friend in a coma, and has been coping with survivor’s guilt by abusing pain medications. However, by fulfilling Urhoa’s challenges, he heals and grows as a person. There are adventures in the aquarium, oceanic demigods, some shocking family history, and a town in danger of being swallowed by the sea.