Produced by OLM and distributed by Warner Bros. Pictures, the story of the film takes place centuries after the events of Ni no Kuni II: Revenant Kingdom, as it centers on two boys named Yū and Haru saving their friend Kotona from danger through Evermore's princess, Astrid.

The film stars the voices of Kento Yamazaki, Mackenyu Arata, Mei Nagano, Maaya Sakamoto, Mamoru Miyano, Yuki Kaji and Kenjiro Tsuda.

That night, Haru drinks away, as he believes this to be a dream, while Yū visits Astrid again, who takes him to the Lake of Purity to dance away the remains of the curse.

The next morning, Yū and Haru are summoned by the mage Gnauss and King Astrum, who make them engage in swordplay against multiple men in order to find out if they were sent by a group known as Black Banner.

A few days later, with Haru still believing it was all a dream, Yū tries to find an old man he met at the hospital during his childhood, but a nurse tells him he has disappeared.

Back in their world, Saki, Yū's adopted sister, is confronted by the same black hooded man at her florist shop when the boys arrive and manage to save her.

He has been plotting to take revenge on his father and the entire kingdom, and manipulates Haru through his armor, which Yū is able to stop with his magic.

In February 2019, Warner Bros. Japan announced at a press conference that Level-5 was producing an anime film based on Ni no Kuni.

Level-5's Akihiro Hino, who created and wrote the Ni no Kuni video game series, served as an executive producer, story and screenwriter for the film.

[5] Other cast members were revealed that same month, with Maaya Sakamoto as Saki/Bertha, Mamoru Miyano as Gnauss, Kenjiro Tsuda as Galeroth, Kōichi Yamadera as Barton, and Yuki Kaji as Dandy.