Chisato visited a hot spring resort with her family of four for the first time in a while, joining her only daughter Mizuki and Mizuki's husband Kenji. She had planned to relax in the outdoor bath to recover from prolonged work fatigue. However, staying in the bath too long caused her health to deteriorate, and she collapsed from overexertion and cold exposure in the bathing area. Witnessing this, Kenji rushed over, picked up Chisato's limp body, carried her back to her room, and warmed her up with a soothing hot bath. That night, Kenji couldn't get the feeling of Chisato's body out of his mind, his desire growing uncontrollably. Taking advantage of everyone's drunken state, he gradually began making bolder moves toward her. An almost dreamlike night unfolded.