When their father comes back from war, Sarah and Lily visit the beach on vacation with their family. Soon they find themselves in a new magical adventure. Following a mermaid past the tide, they enter the beautiful ocean realm of the merpeople. There they learn that a Sand Wizard has moved into the sandcastle they built Enlisted to help the mermaids fight this new evil, Sarah and Lily go on an underwater adventure that takes them through the Bermuda Triangle, across Atlantis, and down the great Abyss to the bottom of the sea. As a hurricane threatens to wash them away, Sarah and Lily must navigate the sandcastle and finally face the terrible Sand Wizard before they fall asleep. Written by a deployed U.S. Soldier to connect with his children, the story is a sequel to The Fairy Child.