Kazuya Mukai, a 32-year-old aspiring mangaka, tumbles off his old elementary school's rooftop in a drunken state. Upon awakening, he discovers that he has traveled 20 years back in time and returned to his sixth-grade self. With the opportunity to rewrite his dismal and embarrassing past, Kazuya sets out to capture the heart of his very first crush, Anna, who was just a little girl at the time. Nonetheless, his emotions trigger a new calamity - a young love that defies time but is ultimately tarnished.
