In where Sunghoon has a crush on Heeseung but Heeseung doesn't, Sunghoon keeps bothering and bothering Heeseung. One day Sunghoon made a deal with Heeseung That Sunghoon has to make Heeseung fall in love with him in 1 Month or 30 days if he doesn't fall in love with Sunghoon, He will dissappear from his life, like he never existed before.. But.. What Heeseung doesn't know is that, Sunghoon has heart failure/problem 4 months ago before he met Heeseung (no one had been wanting to donate their heart to Sunghoon) then and he fell in love with Heeseung when he only had a 2 months to live (He made the deal with Heeseung when he only had 1 month left) so if Heeseung doesn't fall in love with him, at least he can feel happiness, feelings and falling in love with someone before he dies...