Joo-hyung and Na-gyeong live together without a choice. Neat and organized Joo-hyung finds it hard to live with carefree Na-gyeong. Meanwhile, Joo-hyung and Na-gyeong are invited to perform a duet at a party thrown to celebrate moving. After performing, Joo-hyung becomes curious about Na-gyeong. Late at night, the two set out rules at home, and the wine keeps flowing.