After mermaid Marina saved Prince Eric, he betrayed her, massacred her people and killed her twin sister to seize the Soul of the Deep. She bartered her voice for painful human legs and infiltrated the royal palace as a mute maid. Teaming up with a vengeful alchemist, she used poison and illusions to torment Eric and his fiancée. At last, she awakened ocean fury, took back her sister’s relic and brought brutal retribution to all betrayers.