Morag's summer trip with her family and friends to a castle in Orkney, Scotland could fix all her problems. There's no way her parents will keep fighting once they're back in the place they honeymooned. Her best friend's hot brother will have to notice her when they spend months together. That AP art class she has to retake? She'll pass it this time, now that she's thought of the best theme for her portfolio: Orkney mythology.

Only it doesn't take Morag much time on the island to suspect Orkney mythology might be less myth and more fact. Strange lights in the water, odd footprints in the castle, and shadowy figures are only the beginning. It's obvious the islanders are frightened of something in the sea, and that Morag's family are unwelcome.

As the summer solstice approaches, Morag's problems condense down to one: Get everyone off the island-alive. But the only way that can happen is if Morag figures out who she truly is before time runs out.