Jiro (Keisuke Koide), a college student who lived a lonely life without anyone wishing him a happy birthday, suddenly met "her" (Haruka Ayase) on his 20th birthday. The two spent a wonderful night together. That night, "her" disappeared from Jiro's sight. One year later, on his birthday, Jiro, who thought he would return to a lonely life, met "her" again. This time, "her" told a shocking story: "I am the robot created by you, Jiro in the future, and I went back to the past to protect you from disasters." In this way, "her" moved into Jiro's house and began to live with Jiro. Disasters did not seem to leave Jiro, but Jiro's feelings for her had already sprouted. A touching story of love and time, guarding the promise of the future, and starting today's life.