Sea Hidden is an innovative book with an elaborate puzzle published with a prize for solving the puzzle. In Sea Hidden, a young Mermaid races with a monstrous villain to solve clues embedded within an ancient civilization's traditions and literature. In the process, she gets caught up in that cultures stories about the ancient alchemists, guardian hybrids, and their struggle with an evil emperor. These are stories that come to life for her in both wonderful and terrifying ways. She discovers family members she never knew she had, and is introduced to their secret hidden civilization at sea. But she must also confront a deranged hybrid who has confused her with the founder of this civilization, and is trying to kill her.