On Australia’s Gold Coast, an ordinary girl enjoys a quiet life with her family and her close neighbour, Tom Felton. During a seemingly harmless camping trip to a nearby, dangerous island, she stumbles upon a hidden cave under the volcano, where she discovers a Moon Pool beneath a volcanic crater. After falling in under the full moon, she unknowingly undergoes a life-changing transformation. Back home, everything feels normal, until water touches her skin and she turns into a mermaid.