"I'll teach you to behave!" Vernon Dursley shouted as he backhanded Harry Potter and sent his broken glasses flying. "No more food for you, you freak!"
He grabbed Harry by the scruff of his neck, dragged him to the storage closet beneath the stairs, threw him in, slammed the door, and padlocked it.
That's strange, he thought. That door looks a bit different today.
Harry rolled over with a groan. That's strange, he thought. It isn't dark in here.
He rose to his hands and knees, and spit blood on the floor. The closet was bright, and stretched into the distance as far as he could see. Without his glasses, that wasn't far, but the closet under the stairs was definitely larger. It was filled with machines. A small girl, with wild red hair, was sitting in mid-air typing. She looked over at him, stood, and hurried to his side.
"I don't like the looks of that blood," she said. "What happened?"
Harry told her, and his world was never the same again. Neither was the Dursleys'.