Kim Gyeong-tae knows exactly how stories like this are supposed to end.

He's just a supporting character in a youth sports romcom, so staying out of the spotlight should be easy. A pair of plain glasses keeps his looks hidden, badminton is just a hobby, and watching the original protagonists from the sidelines is good enough for him.

Then the confession that should have brought the main couple together falls apart.

When his childhood friend starts looking at him instead of the original hero, Gyeong-tae realizes that changing the story is much easier than avoiding it.