When Jade's hormonal change into womanhood also includes developing scales and a tail, she discovers she's inherited her mermaid tendencies from her late mother, and it prompts her to investigate how her mother died.
While unrest stirs the mer-world, Jade faces the challenges of ninth grade, including seeking a plus-sized dress for the Fall Formal, keeping her mer-ness secret, and figuring out if she and Luke are officially dating.