My sister, Umi, came to Tokyo for her studies and will be staying with me, her older brother, for a while. Living together with my sister, whose hometown dialect remains unchanged, was quite endearing and enjoyable for me. However, one day, without any particular reason, I, without considering my age, engaged in a playful wrestling match with my sister. When I saw her teary-eyed reaction, which was oddly submissive, I couldn't help but feel a sudden chill...!