After his stepfather passed away, Yuri became a widow. Atsushi and his wife came to check on Yuri who was left alone in the countryside. As a son-in-law, he genuinely cared for his stepmother, but Yuri was too young and beautiful to be called 'mother.' With the barrier of his stepfather gone, Atsushi's feelings for Yuri were uncontrollable, and Yuri herself was unable to control her emotions and body due to loneliness. In that moment when they were alone together, their thoughts intertwined, crossing a line that should not have been crossed…
