After my father's remarriage, I suddenly found myself living with my new stepmother. At 30 years old, she's almost the same age as me—an irresistibly attractive woman radiating pure sex appeal. Day after day, her constant flirtatious behavior keeps me in a constant state of arousal. When the three of us gather around the kotatsu and my father passes out drunk, I end up having passionate sex with my stepmother right beside him. An explosive, shocking turn of events unfolds in the midst of everyday life.