A red band, a ring, connected to a fateful opponent. When a red ring appears on the ring finger of your left hand, you cannot fall asleep unless you are in contact with that person. And I was in the ring with the brother of the person I had a crush on for 5 years... Shin Woo-seo, who has had a crush on his friend for the past 5yrs is suddenly link to Ji-Gun Kang, the older brother of Ji-Suk Kang who's his unrequited love. Ji-Gun Kang who repressed his feelings of Shin Woo-Seo for the past 3yrs is suddenly filled with an overwhelming feeling that was close to ecstasy once the red ring appeared. Ji-Gun plans to change the shape of their formal relationship, even if Shin Woo-seo doesn't want it.