After his wife Eri was involved in an accident and hospitalized, Satoshi found himself living alone. Around that time, his mother-in-law Yuko came to stay with him. Yuko efficiently handled all the housework, and her presence began to exude a special charm in Satoshi's eyes. Watching her run the washing machine or wipe the floors during her free time, Satoshi couldn't help but gaze at her with growing desire. Amidst this, he recalled how on the day of the accident, Eri had been gently embraced by Yuko. That memory burned in his mind, and Satoshi could no longer suppress his feelings for her.