Yosuke, who was living at his brother's place, felt guilty but had developed feelings for his sister-in-law Aoi. One day, Yosuke saw Aoi masturbating due to her sexual frustration. "Please! Just once!" he begged, prostrating himself to request a physical relationship with her. "...You absolutely must keep this a secret from him?" Surprisingly, Aoi, who had been pent-up for quite some time, agreed to Yosuke's request under the condition of 'sotokoni'. However, Yosuke had prepared a certain secret drug for this day...
