Ji Yul-moo, a freshman student with thick glasses and baggy clothes, who seems to know nothing but study.
Unlike her innocent looks, she always carried a green notebook that full of wild stories containing her perverted desires.
Then one day, Jeongwook, a senior that she always envies, discovers her lewd notebook...

"I really wanted to meet you, Ji Yulmoo."
"Me? Why...”
"I was really impressed by this. The story you wrote."
“...!”
"Shall we talk?"

Rather than criticizing Yulmoo, Jeongwook invites her to his X-game club...