Sore Ike! Anpanman: Ningyohime no Namida

Sunny, a mermaid princess living in the underwater Uzumaki Castle, longs to experience the world on land. She secretly takes a magical red starfish hair ornament that can give her a human body and soon finds herself welcomed by Anpanman and his friends, especially the kind Shokupanman.

The ornament carries a curse Sunny does not understand. By taking it away, she helps awaken the legendary stone monster Gorongora, and Baikinman is quick to exploit the disaster beneath the sea. When the ocean itself is threatened, Sunny must face the consequences of her wish and find the courage to protect both the world she came from and the friends she found on land.