Yoon Jin Ah is a single woman in her 30's. She works as a supervisor at a coffee company. Yoon Jin Ah is an easygoing person, but she feels empty inside. Seo Joon Hee is the younger brother of her best friend Seo Kyung Sun. He comes back to South Korea after finishing work abroad. Yoon Jin Ah though he was just a childish guy, but he appears different to her now.