The Man Who Stole the Sun (1979) is a Japanese film directed by Kazuhiko Hasegawa. The story revolves around a high school science teacher, Makoto Kido (played by Kenji Sawada), who becomes obsessed with building an atomic bomb after becoming disillusioned with the state of the world.
Despite the ridicule he faces from his students and colleagues, Kido manages to successfully construct a nuclear weapon in his apartment and decides to use it as a means of blackmailing the Japanese government into admitting their faults and shortcomings. However, his plan spirals out of control and he becomes a wanted criminal pursued by the police and the American military.
As Kido becomes more and more unhinged due to the power he holds, his former love interest, a fellow teacher named Yumiko (played by Bunta Sugawara), attempts to stop him from carrying out his mission while also trying to convince him to surrender to the authorities.
The film explores themes of power, responsibility, and the consequences of unchecked ambition in a world where technology has advanced to the point of being able to destroy mankind. It received mixed reviews upon its release but has since gained a cult following.