Theatrical release date: April 10, 2026.

Synopsis: In a fantastical future, humans and mermaids share a troubled coexistence.

Stephan, an anxious employee at a shipbuilding company, has big ideas to save the sea. But his life explodes into ecstatic chaos when bubbly mermaid princess Chao proposes marriage out of the blue.

Between shopping sprees, giant robots, and actual fireworks, the unlikely pair flounder through their new romance and unlock their true feelings.

Directed by Yasuhiro Aoki.

Character designs by Hirokazu Kojima.

Music by Takatsugu Muramatsu.

Japanese voice cast:
Ouji Suzuka as Stefan
Anna Yamada as ChaO
Yuichiro Umehara as Roberta
Ryota Yamasato as President Shi
Kavka Shishido as Maibei
Cookie! as Ambassador Omede
Kenta Miyake as King Neptunus
Shunsei Ota as Juno
Anna Tsuchiya as Editor-in-Chief