Amidst the mermaid civil war, the Empress stripped Princess Aria Trueblood—the heir with a sacred mission—of her powers and exiled her to the mortal realm. Four merfolk closely tied to Aria transformed into a doctor, a celebrity, a CEO, and a mafia boss to infiltrate the human world. Their quest: Find Aria, uncover why she vanished... and confront her mortal incarnation, Luna, in a story of fire and tides.