Once upon a time, the world was divided into two parts, one part belonged to giant people, and the other to small ones, the size of a finger, they were not allowed to see each other because it was very dangerous for small people and could harm their lives. Rui was just a giant who did not know about the existence of such people, he lived in happy ignorance, but one day, when he was having breakfast, he saw that someone was crawling on his clothes, he took the guy by the collar and lifted him up, not knowing who it was, soon he noticed a sign with his name on it. "You're so small, Tsukasa-kun, it's dangerous here."