Captured by Zog, Trot and Cap'n Bill face imprisonment in the lair of a sea monster. But aided by mermaid magic and the mighty King Anko, they stage a daring escape. Battles atop a grand dome reveal their courage and Zog is ultimately defeated. The ocean monarchs and allies come together to restore peace to the sea. In the end, Trot returns to the surface world, forever changed by her unforgettable adventure beneath the waves.
