"You'll be Sorry!"

"I said you were not getting past us.” Sam began to laugh. Just as Mark stood up again he heard a voice come from behind him.
“Leave him alone!”
What now? He turned and noticed a small girl standing there.
She was about Mark's age, eight or so, standing there pointing her finger at Sam and Bobby Jenkins. Sam just scowled at her and then they both laughed. “What are you going to do about it?”
What happened next was a shock even to an eight-year-old boy. She said, “You’ll be sorry.”