100 candidates of God and Mr. Koba is one of them. Each candidate can give ‘talent’ to a human to test his sense of justice. Mr. Koba chooses Kosuke Ueki. He’s a top student with reckless attitude. Koba gives him a talent to change anything he grabs into tree.
Every body has talents. That could be the talent to be liked, to like, to hit or to be a fast runner. That’s what we call ability. For ueki, the ability has one condition. If he uses his talent to hurt people, he will lose his talent, one by one.