After years of abuse, Emily finally discovers she's the biological daughter of the wealthy Lancaster family. But her homecoming is far from a fairy tale. Her parents and brother Adrian openly favor Lena, the girl who took her place. Determined to reclaim what belongs to her, Emily fights back—until she discovers Lena's shocking secret: she's a mermaid! Emily initially uses the secret to force Lena to surrender her inheritance rights. But as they grow closer, she realizes Lena isn't her real enemy. Their parents have been sacrificing mermaids to prolong their lives. Emily rescues Lena and exposes the family's horrifying crimes. Together, the two women uncover an illegal mermaid experimentation and trafficking operation. After bringing the criminals to justice, they finally admit their feelings. Lena returns from the sea and chooses a future with Emily.
