I'd give up the stars

Most people, when they tell someone they'd give up all the stars in the sky for them, they don't mean it literally.

But they do.

"Kōshi~! Hurry up!"
"Shut up Tōru, I'm coming!"
"Tetsuro, did you take my shoes?!"
"No I didn't Keiji!"
"I'm tired Ryunosuke."
"Go bother someone else, Lev."

Six boys travel to Earth on a journey to learn about human culture in secret. However, when those six boys meet six other boys, things start to change. They stray away from their original mission.

Will it be for better or for worse?