SM University is an all boys University. There is a rule that all student needs to obey and that is, LOVE is forbidden behind and outside the doors. Anyone caught having a relationship behind the Principal backs, will be expelled for good. The traditions were obeyed for years but when 3 boys from different backgrounds arrive at the University, changes started to happen with the help of the University newest Professor, Yunho.

Characters :

Lee Taemin :
A student in SMU. Taemin is a soft and kind person who likes to help everyone. People take advantage of his kindness and bully him. He is bestfriend with Krystal who always defend him if he gets bullied. As he enter SMU, he finally realise that his fondness for Krystal is actually love. But it's hard to win her heart when it's already be taken by a wealth boy.
 

Kim Jong In :
A student in SMU. Jongin or known as Kai by his friends, is an orphan. He is a cold and a loner in the school. He hardly trust anyone because of his past. But as he enter SMU, he found someone aside from Taemin and Tao, that he could share his trust with. But the problem is, she only thinks him as a younger brother.
 

Huang Zitao :
A student in SMU. Tao is a playboy who hits on all ladies he could get. He breaks their heart after he gets bored with them. He nevers believes in true love and thus make him into like this. But as he enter SMU, he finally found his true love but with his famous reputation as the ladies man, it's a hard lady to get.
 

Jung Yunho :
A professor in SMU. Yunho teaches Dance and Music in the University. Secretly, behind Lee Soo Man back, he encourages his students to break the important rule in SMU. Always bailing the students out of trouble when Lee Soo Man caught them.
 

Krystal Jung :
A waitress in a small cafe. Krystal used to live with Taemin before Taemin left home to stay in SMU dorm. Krystal is protective of Taemin because people always bullies him. While Taemin in SMU, Krystal heart was taken by a wealth boy which Taemin hates.
 

Im Yoona :
A widow with a son. Yoona lives with his in-laws eventhough her husband had died. She owns an orphanage for which Kai always come to visit. Yoona treated Kai as her younger brother and rejected his love for her when he confess. In her mind, her husband is still alive since the dead body wasn't yet discover.
 

Kwon Yuri :
A student in an all female school like SMU. An arrogant, y and beautiful girl. Yuri hates playboys and when Tao tried his best to get her heart. She make him regret that he ever choose her as his true love.