The Door into Summer is a 2021 Japanese science fiction film directed by Takahiro Miki and starring Kento Yamazaki, Kaya Kiyohara, Naohito Fujiki, Natsuna, and Hidekazu Mashima. Based on Robert A. Heinlein's novel of the same name, it was released on June 25, 2021.

Kento Yamazaki is a Japanese actor and model. He is best known for his roles in the films L DK (2014), No Longer Heroine (2015), Orange (2015), and Kingdom (2019), as well as the TV shows Death Note (2015), Kiss That Kills (2018), Good Doctor (2018), and the Netflix series Alice in Borderland (2020–present). He is under the Japanese talent agency Stardust Promotion.