The sleepy seaside village of Porthaven hides a mystery ...Mia's grandad has vanished and nobody knows why. When Mia and her mum go to support her grandma, Mia makes friends with local girl, Dee. But why does Dee seem so out of reach? Why does she claim to be facing violent storms when Mia sees only sunny skies? And can Mia solve the mystery and find her grandad before time and tide forever wash away his future?