Cocoon—One Summer of Girlhood, an anime film directed by Yukimitsu Ina, is set to premiere in U.S. theaters on September 4. The film, which debuted in Japan in March 2025, will be available in both subbed and dubbed formats. It is based on the josei manga by Machiko Kyo and tells the story of two girls coping with the harsh realities of war while attending an all-girls school on a serene island.
The narrative follows characters San and Mayu as they are compelled to assist in a military hospital hidden in a cave when conflict reaches their peaceful home. The screenplay was co-written by Ina and Taku Kishimoto of Sakamoto Days fame. The film marks the first feature from the animation studio Sasayuri, established by former Studio Ghibli animator Hitomi Tateno, alongside other Ghibli alumni.
Notable contributors include animators Akihiko Yamashita and Shinji Ōtsuka, with a score composed by Kensuke Ushio. The Japanese voice cast features Marika Ito as San and Hikari Mitsushima as Mayu, while GKids plans to reveal the English voice cast later this summer.