Ikumi is a highly capable woman who excels at work and enjoys living alone. At home, she wears glasses and lounges around in sweatpants, living a rather lazy and carefree life. One night, she receives a sudden call from Kouki, her coworker and junior from the same intake year. He claims he missed the last train and got lost, so reluctantly, she agrees to let him stay over. However, from that night on, Kouki keeps using the excuse of missing the last train to overstay at Ikumi's place more and more often.