Won Yoo-il, who is always bullied every Monday because of the name he has. Feeling devastated, Yoo-il dropped out of school and moved to a new high school. Yoo-il's new classmate in third grade is Goo Yoon-won. At first, Yoon-won looked like a jerk, but he wanted to keep sticking with him, and this annoyed Yo-il. Until one day, he sent him a note saying that he wanted to be his second Hyung.