As Siren approaches her twelfth birthday, she discovers a fantastical truth: she's destined to become a mythical mermaid. Amidst the chaos of transformation, she must bid farewell to her ordinary life and friends, while evading ruthless hunters seeking to capture her. With the help of Adam, a new ally, she must navigate treacherous waters and confront her own father's sinister intentions, all while staying one fin ahead of danger.

Runtime: 92 min