Due to her husband's business trip being delayed for a few more days, Ai felt extremely lonely. During this time, as Ai's sister was on vacation, she asked Kazuo to stay at her house for three days. Feeling sexually frustrated and with no other outlet, when Ai met Kazuo, she desired to have sex with him. Despite her seductive advances, Kazuo, a diligent student, remained steadfast and unmoved. At this point, Ai had to resort to her final move. While Kazuo was asleep, she sneaked into his room in lingerie and used all her sexual skills to make him unable to resist. Ai succeeded, she put a condom on him and took his virginity, her younger studious brother's. Unbeknownst to her, she had awakened the lustful demon within Kazuo. He thrust his bare cock straight into Ai and ejaculated all his semen deep inside her. He continued to have sex with Ai repeatedly, despite her pleas. And for three days Kazuo was there, almost always entwined with each other, with Ai always filled with the thick semen that Kazuo had been accumulating for many years...