When the king of the mermaids is poisoned, Lily is called to help with a problem she’s never faced before—one beneath the surface of the water. As she sets about creating a potion to save his life, however, she realizes this is only one part of a much, much larger problem. One morning, Lily receives a letter from an anonymous source stating that The Faction is planning to launch an attack against The Isle. Can Lily stop her father and The Faction before it’s too late? Time is running out, and Lily can’t help but feel she’ll need a miracle to save the lives of the ones she loves…