One day, during a record-breaking midsummer day, I was planning to enjoy dinner with my wife's family at home. While my wife went to pick up her mother-in-law, I was left alone with my wife's older sister, Ayaka, whom I had always had a crush on, and I struggled to keep my sanity... Then, as the sun went down, the moment I stood in the kitchen to make dinner, we were hit by a major power outage. Due to a sudden accident, I ended up spending the night alone with Ayaka, and I couldn't contain my excitement at the sweat dripping down her body...