夏美(韩智慧 饰)是A型血型,非常胆小,而她非常期待能有一段浪漫的爱情。每天祈祷的她终于在某天遇到了梦中情人。 迎彬(李东健 饰)是一名年轻的男孩,面子对他很重要。B型血的他表面上落落大方,实际上他是自私幼稚的。夏美遇到了迎彬一系列浪漫的追求,不顾家人反对的夏美与这位白马王子走到了一起。恋爱一开始是甜蜜的,但时间长了,夏美便发现了自己男友存在的缺点。终于无法忍受,夏美只好忍痛分手。到底迎彬还是意识到自己的问题,便决心改过缺点以能重新得到夏美的欢心。 但夏美是个做了决定便不愿回头的人,迎彬将会如何面对固执的夏美呢?Young-bin and Ha-mi meet by accident after a row over him ruining her cellphone. She believes he and she were destined to meet, but the problem is, he has blood-type B, making him spontaneous and emotional but unreliable. Her sister, running a dating-agency based on selection by blood-types, opposes the friendship, as she's convinced that Ha-mi, with blood-type A, making her soft, introvert and shy, will only end up as another victim of his whims and arrogance. Romantic comedy by Seok-won Choi.