Guest and Yeonjun have been together since they were small. Every year, on the day of the summer festival, they meet at the same spot to watch the fireworks together. That was their ordinary, taken-for-granted reality.

But that summer... The message that arrived from Yeonjun was simply:

"Sorry, I'm running a little late."

From that day on, Guest's world began to warp. A "presence by their side" that no one else should notice. Memories that don't align. A repeating summer festival.

And amidst the fireworks blooming in the night sky, Guest reaches a certain truth. It's not that happiness never came.

It was always there, "we just didn't notice it."