Ruler by day, a reluctant pirate by night, 18-year-old Princess Ariana fights for her subjects in the waterfall city of Lunadar. In a kingdom surrounded by fairies and mermaids, and ravaged by deadly Drundles, only a chosen few are trusted to guard her daughter, Candra, as the secret heir to the throne. But it only takes one ill-fated meeting for Ariana to suddenly be plunged into an escalating web of secrets found in her father's journal, a deadly kidnapping, and an ever-weakening resolve to turn her back on the call of the merman's song. With Ariana's world falling apart and the future of Lunadar at stake, how will she bring her father's murderer to justice and fulfill a deathbed promise to protect Lunadar's legacy?