Eunwon, who has a one-sided crush on their older brother, Woosuk, has been living with him for a year. Actually, Woosuk is not their biological brother, but their older step-brother...however, to be close to him, Eunwon even cross-dressed and became his roommate. They anticipated a heart-fluttering campus life, but everything changed after a night with a drunk Woosuk at a club gathering. Woosuk acts like nothing happened, having no memory of the event, leaving Eunwon confused. Finally, Eunwon decides to sleep with the drunk Woosuk again... “Brother...no, oppa, do you want to sleep with me?”