Kim Yun-su spent his twenties working overtime, paying off debts, and watching his youth slip away.

Then he wakes up inside his favorite romance-comedy, not as the handsome protagonist, but as Seon Woo-hyun, the loud comic-relief extra whose biggest job was making everyone else look cool.

This time, Woo-hyun has no interest in acting like an overgrown child. He studies, works out, treats people with quiet respect, and finally enjoys the ordinary school life he never had.

The problem is that the more he ignores the story's heroines, the more they start paying attention to him... and the original love story slowly begins falling apart.