Kanta Kakuhata has spent eight years as a shut-in, living at home under his mother's care, with zero romantic experience. When she falls ill and receives a terminal diagnosis, Kanta, flooded with regret over all the trouble he's caused her, comes face to face with his mother for the first time. Gazing outside the window at a billboard featuring Mami Hamamiya, Japan’s top idol, his mother tells him she once dreamed he would marry someone just as beautiful.