Jang Seon-kyul (Yoon Kyun-sang) has wealth and good looks but suffers from severe mysophobia. He is obsessed with cleaning and even owns his own cleaning company. However, he meets a carefree and untidy girl named Gil Oh-sol (Kim Yoo-jung) after she enters his company as a new employee. Oh-sol has worked all sorts of part-time jobs while striving for a full-time job and does not have the luxury to date or clean. She gave up on being neat after facing the tough reality of the world and is known for always wearing her trademark tracksuit. But she has a bright personality and does not mind getting dirty. With the help of Oh-sol, Seon-kyul faces his mysophobia and also falls in love with her.