Produced by TMS Entertainment and distributed by Toei Company, the film is directed by Kenichi Kasai from a script written by Riko Sakaguchi and stars Hio Miyazawa, Aju Makita, Ai Hashimoto, Mutsumi Tamura, Kenji Hamada, Mie Sonozaki, Tomomichi Nishimura, Miki Mizuno, Kimiko Yo, and Tokuma Nishioka.
The film follows Koyomi Hidaka and Shiori Satō falling in love with each other, but their parents' remarriage has led them to elope to a parallel world where they are not stepsiblings.
Koyomi expresses his desire to save Shiori, so he helps in the experiments about Parallel Shift while keeping on attending high school.
Koyomi later reveals that he is researching the Time Shift to send Shiori to a world outside of her event radius, which refers to her accident.
Koyomi still fails to make the Time Shift possible but after hearing Kazune's mention of the buoyancy and viscosity of a beer, he takes these concepts to solve his research.
An anime film adaptation of one of the two science fiction romance novels by Yomoji Otono, Kimi wo Aishita Hitori no Boku e, was confirmed in September 2021.
[14][b] In May 2022, Kenichi Kasai was revealed to be directing the film at TMS Entertainment, with Riko Sakaguchi writing the script and Shimano conceiving the character designs.
[16] In June 2022, Hio Miyazawa, in his voice acting debut, and Aju Makita were revealed as the main characters Koyomi Hidaka and Shiori Satō, respectively; Miyazawa was also set to voice Koyomi Takasaki alongside Ai Hashimoto as Kazune Takigawa in the film's companion piece To Every You I've Loved Before.
[5] Mutsumi Tamura, Kenji Hamada, Mie Sonozaki, Tomomichi Nishimura, Miki Mizuno, Kimiko Yo, and Tokuma Nishioka were announced as part of the cast in August 2022.
[17] That month, other staff working on the film were also announced, including Kenzō Ishiguro for planning and production, Yukari Tachibana and Tomoyuki Saito as the producers, Shinichi Machida as the character designer, Yukari Takano, Erina Kojima, and Noriyasu Murata as the animation directors, Yasutada Kato as the art director, Yūsaku Murakami as the cinematographer, and Keisuke Yanagi as the film editor.
[1] In September 2022, vocalist Shinya Ishihara of the Japanese power trio band Saucy Dog was confirmed to be making a guest appearance in the film.
[17] In September 2022, Saucy Dog was also set to perform the insert song "Summer Daydream" (サマーデイドリーム, Samā Deidorīmu) for the film.
[27] That month, the film was included in the benefits of premium users of au Smart Pass [ja], where they could watch a work at theaters for ¥1,100.
"[41] MrAJCosplay at Anime News Network found the film better than to its companion piece in giving "explanations and expository scenes" due to fact that it focused about parallel universes.
They lauded how the first thirty minutes of the film gave a focus on the romance of the main cast, while the final two-thirds of the runtime were "far more plot-driven."