After being dismissed as a hopeless failure by people around him, 27-year-old Arata Kaizaki hops around from one job to the next after leaving his first. His humdrum lifestyle changes dramatically when he meets Ryou Yoake, a member of the ReLife Research Institute, who gives Arata the chance to transform his life for the better by taking a strange pill. Arata accepts it without hesitation and awakens the next day to see that his look has reverted to that of a 17-year-old.