After the death of their parents, brothers Kangin, Donghae and Kyuhyun are placed in the care of their mother's sister. Being the chancellor of SM University in Ulsan, their aunt enrolls them all into the school to continue their education. Mysterious, quiet and sinfully handsome - everyone wants to get to know the three brothers. Unfortunately, each brother keeps away from groups, talking to no one and, not even smiling - all in an effort to hide a secret the all keep.

Kangin's story: Control.

Being the eldest brother, Kangin has always been fiercely protective of his younger brothers. Once the national champion of Tae Kwon Do in highschool, Kangin is still known for his unquestionable strength, even though he quit five years ago. When Eeteuk, coach of the archery team, approaches him to recruit him, he's nothing less than startled.

Donghae's story: Escape.

Being the middle brother, Donghae was never troubled by the stereotypical woes of middle children. Once the most popular of the trio, he now prefers solitude and even wears headphones everywhere to further distance himself from others. One day he meets top student of his year - Siwon - and realizes this is one person he cannot avoid.

Kyuhyun's story: Apathy.

Being the youngest brother, Kyuhyun was always doted on by his parents and brothers. Once considered the most handsome of the brotherhood, he now rejects all confessions from girls and all offers of friendship from everyone else. Avoiding all types of relationships, save that of the brotherhood, his exclusive world is disrupted when he's forced to tutor the tae kwon do team captain, Sungmin.