Emily Windsnap discovers a hidden world beneath the waves and a secret about her own identity. Emily, a young girl living in a seaside town, has always felt a strange connection to the ocean. When she discovers a mysterious locket, it leads her to the underwater kingdom of mermaids. There, she must navigate the challenges of fitting into a new world while uncovering the truth about her mother's disappearance and her own mermaid heritage, all while evading those who wish to keep the mermaid world a secret.

The Emily Windsnap series is often praised for its imaginative portrayal of a hidden mermaid world and its relatable young protagonist. Readers frequently highlight the blend of adventure and mystery as Emily uncovers secrets about her family and her own identity. The books are generally seen as engaging and suitable for younger readers interested in fantasy and magical creatures. The narrative structure typically focuses on Emily's personal growth and her experiences navigating two different worlds.