Dylan was born with two spirits: human and monster. When he and his family dive underwater, they become wyrms, enormous guardians of the seas. Yet Dylan hates his second spirit, and fears he will hurt innocent people. With his family away on a mission to quell a rising danger in the ocean, Dylan takes his chance to change himself for good and feeds his second self to a spirit eater. But things go awry, and Dylan is left half-changed, with the creature ever on his tail. Worse, his family need his help. Dylan must set sail to save them, deciding as he goes who he can trust - and ultimately choose what he truly wishes to be.
