The ocean keeps her secrets. Lo doesn't know who she is. Or who she was. Once a human, she is now almost entirely a mermaid, a term too pretty for the soulless monster she's becoming. Then Lo meets Celia when they work together to rescue a handsome boy named Jude from drowning. Unlike Lo's ocean sisters, Celia has the ability to help Lo remember her human past. The two form a friendship but soon find themselves competing for Jude's affection. Lo wants more than love, though. According to ocean lore, there's only one way for Lo to earn back her humanity. She must persuade a mortal to love her ... and steal his soul.