Mew, Ray, and Boston—a group of business students running a hostel together—blur the lines between friendship and romance. 三位合伙经营旅社的商科学生Mew、Ray和Boston,模糊了友谊和爱情之间的界限。 Mew has been focusing on his studies, setting aside no time for sex and relationships. Upon learning of his friend's innocence, Boston introduces Mew to Top. What Boston intended to be a one-night affair turns into...。母胎单身,情商为零,不知道自己为何而生的自卑处男工薪族·小日向大河(24岁)在上班途中因为某个“小事故”第一次坠入爱河。 他爱上了童颜巨乳的大姐姐·驹田多惠(32岁)。而治愈系的多惠的真实身份居然是一位职业女棋手!? 不在同一世界的自卑处男和美女棋手的姐弟恋就此展开……这份恋情,有罪吗。