Hwang Min Ah (You) just moved back to Korea after 4 years of living in the States. Yook Sung Jae, her best friend, offered her to stay at his place. Knowing, that she couldn't refuse her best friend, she accepted the offer, but what will happen when one of his hyungs falls for her? And to top it off he's also her room mate! Will this drive them both Insane?