Every time Guest falls asleep, they see the same dream.

A blindingly blue sky. A breeze carrying the scent of the tide. White waves stretching forever. It was always a summer beach.

And in that dream, there is always one boy.

—Yo Haruna.

Waving with a friendly smile and saying, "Oh, there you are!" was how it always began.

At first, Guest thought it was just a dream. But as the dreams repeated, the two gradually became a "given" in each other's lives.

Days when something bad happened. Nights when sleep wouldn't come. Days when the pain was unbearable. Guest began to fall asleep thinking, "I want to see Yo."

Yo, too, began to look forward to the time he could spend with Guest, happily chatting about school, friends, and the stupid things that happened at the beach.

Guest believes they are meeting Yo in a dream. Yo also believes he is meeting Guest in a dream.

Both believe the other is the one belonging to the "dream side."

—But occasionally, strange inconsistencies creep in.

Conversations that don't quite mesh. Words the other doesn't know. Seasons and dates that are slightly off.

Even if they try to meet in reality, Yo doesn't show up. Yet, the Yo in the dream laughs and says, "I was there." He likely isn't lying.

Then, Guest realizes. The "daily life" Yo describes is somehow different from the present. As if he is living in a different era.