Jang Sun Gyeol (Yoon Kyun Sang) has wealth and good looks but suffers from severe germophobia. 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 (Kim Yoo Jung) has worked all sorts of part-time jobs while striving for a full-time job and does not have the time to date or keep everything clean. She gave up on being neat after facing the tough realites 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 (Kim Yoo Jung), Sun Gyeol (Yoon Kyun Sang) faces his fear of germs and discovers that he's falling in love with her.