Bobby and Hanbin are best friends, almost like brothers one could say. One day Hanbin's cousin, Min-ji becomes part of the 'fam' as she is their new roommate. However, Bobby is immediately uncomfortable around her. Only to find out she's mentally ill and takes pills to stay right. Hanbin is way over protective with her. Bobby and Min-ji are two completely different people with different mindsets. From two totally different worlds, but when their worlds collide, what's bound to happen?

Minji has been in love with Namjoon from the moment she laid eyes on him. She had never had the courage to tell him how she truly feels out of ruining their friendship. Later on she finds out that Namjoon has fallen for her sister Sunny. Sunny, who is prettier and more popular than her, finds out that Minji has a crush on Namjoon. Minji's life takes a turn for the worst when she finds out her older sister is dating Namjoon. A few years later, Namjoon & Sunny are engaged. Deeply saddened by this event Minji builds up the strength to tell Namjoon how she feels but will he feel the same way?