6 boys who already have a strong bond, and Hwan, an outsider who just arrived in Songju. One misunderstanding leads to a conflict between Hwan and the other boys. In the end, Hwan realizes that his prejudice was the problem, not the boys.

The boys begin to clear up their misunderstandings and understand each other's pain. They become closer than family as they prepare a birthday party for Cein, who has always been alone.

The boys rely on each other more than their families, more than anyone else. However, some secrets they bury in their own hearts become lies and secret wounds.

They barely manage to live their own lives, yet they become superheroes when they have to protect each other. But they don't have any flashy gadgets like Batman or powers like Superman.he boys begin to clear up their misunderstandings and understand each other's pain. They become closer than family as they prepare a birthday party for Cein, who has always been alone.

They become each other's earth, the only place they can live and breathe. An insignificant microcosmos covered with scars, but they still keep dreaming in their own little world.

Just as fish of the same species evolve into different forms under the influence of their environment, the boys have grown into their own personalities over the past half year, for better or worse…

They become each other's mirrors, which allows them to realize their own pain even more clearly. They have no idea that their own pain will hurt the others like broken shards of a mirror.

The boys confess their secrets to each other in the same way they would to a Catholic priest. Strange confessions from young boys who have no sins to atone for, just like how people sacrifice only the purest lambs.

Huge dangers that are so close yet go unnoticed. Like the asteroid in 2019 that flashed by us without anyone noticing.

The trauma that made the young boy suffer had forced him to hide. But the boy refuses to hide anymore and decides to find the truth.

The boys put all the events behind them and moved on with their lives. But a single note starts to connect them once more.

The boys, while adapting to their own lives and beginning to find individual solutions, are confronted with unbearable tragedies that repeat like a treadmill. The boy who realizes the truth takes a step from the end toward a new beginning.