It's been a year since her husband died... Her daughter Hitomi is now married and living alone. Her only joy is the conversations she shares with her son-in-law Daichi, who comes over to visit her every now and then. However, as Hitomi begins to see Daichi as a man, she is unable to suppress the urges smoldering inside Kokoro and gives herself to him. Having crossed the line, their relationship changes drastically, and Hitomi becomes obsessed with the warmth of Daichi, who passionately seeks her every time he visits. But one day, Miku becomes suspicious of their behavior and visits the house...