"Shipwrecked" in the small village of Rincon, Oregon, Amanda Cumberland and her brother Sam, find themselves surrounded by a different breed of mermaid. These mermaids roam freely between land and sea. By day, local youngsters learn about mermaid history in school while the mermaid adults tend their shops and eateries, keeping watch on mermaid matters by night. Then the Siren Queen launches her nefarious plans involving shifting tectonic plates and kidnapping in her efforts to obliterate the "two-leggeds". Suddenly, Amanda finds herself training with battle-ready mermaids and discussing history with curious water sprites working as scientists and scribes. After accepting her own mermaid physiology, Amanda will discover her inevitable connection to an infant and the rescue of the mermen who have been missing for over 200 years.