Kyuhyun is 19 years old. He is a good boy but with a dark past. He meets a challenging but very attractive boy at the University who rocks his world completely. This boy, ‘Mad’ Choi Siwon, with 19 years old too, who spends his days fooling around with girls and earning money in secret fights, will move his world with a bet. If Kyuhyun wins, Siwon won´t date anyone for a month but if Siwon wins, Kyuhyun will have to spend a whole month living with him. Siwon never imagined that Kyuhyun would be the only beautiful thing in his disastrous life. He will become his calm, the only real in his life that will be worthy to fight for.