Sixth-grade student Kanna Hayama's love of running becomes a source of grief when she loses her mother Yayoi, whom she shared this passion with. However, her disposition changes after she accidentally discovers an astonishing truth about Yayoi.

One day, Kanna unexpectedly encounters a divine messenger in the form of her favorite rabbit Shiro and a demon boy named Yasha. They reveal to the girl that her mother was an "Idaten"—a descendant of the gods endowed with incredible speed and entrusted to bring offerings from all over Japan to the annual Kamiari Festival in Izumo. As Yayoi's daughter and the new possessor of the Idaten amulet, Kanna is expected to take over this responsibility; otherwise, there will be dire consequences for the country's fate in the year to come.

Enticed by the prospect of seeing her mother once more at the deities' event, Kanna accepts the challenge and enlists Shiro and Yasha to help her on her quest. Unbeknownst to her, there is more than meets the eye to this marathon-like journey that will test not only her physical condition but also her heart's resolve.

Kamiarizuki no Kodomo is a Cretica Universal project, financed through three crowdfunding campaigns on Sony’s First Flight website from March 27, 2019 to June 1, 2020. While initially planned to be released in 2020, the film was delayed to 2021 due to the COVID-19 pandemic. Anime Expo Lite 2021 hosted a preview of the movie on July 3, 2021. Netflix streamed the film on February 8, 2022 after acquiring its distribution license.

Inspired by the Japanese mythology behind Izumo's Kamiari Festival, Kamiarizuki no Kodomo is an original story by Cretica Universal's founder Toshinari Shinohe, who aimed to express and convey Japan's rich culture to the world. A sticker rally was held in Shimane from October 8, 2021 to February 28, 2022, allowing visitors to see locations associated with the movie and obtain special stickers at three designated points.

Kodansha issued three books based on the movie prior to its release on August 12, 2021, September 15, 2021, and September 30, 2021, respectively. The first was co-authored by the original creator himself; the second was a novelized version of the film; and the third was a picture book.