At nine that evening, Zhang Xiao stood in the deserted Washroom and took out the Time-Turner, slipping its fine gold chain around his neck.
No more than eight hours a day. I used one hour for the experiment, so that leaves... seven turns.
Zhang Xiao twisted the Time-Turner, counted seven turns, then let go. It shook violently, far more fiercely than it had after a single turn.
An immense force tugged at his back, hauling him into the air. His surroundings blurred into bright blocks of color, as though someone had knocked over a bucket of paint.
When his feet touched the ground again, Zhang Xiao found himself on the Great Hall's marble steps. Sunlight streamed through the high windows, casting shafts of light across the empty entrance hall.
Specks of dust flickered in and out of sight within them.
"Good afternoon, Mr. Zhang."
Professor McGonagall stood on the second-floor landing, holding a thick stack of parchment and looking at him in surprise.
"Good afternoon, Professor McGonagall."
Zhang Xiao smiled in greeting.
"If I remember correctly, you should be in Care of Magical Creatures right now."
Professor McGonagall fixed him with a stern look over her glasses, her lips pressed together.
Her gaze fell on the fine gold chain around his neck, and the murderous look on her face softened.
"I take it you've used it already? How many hours?"
"Seven hours."
"Seven hours?" The corners of Professor McGonagall's mouth, which had only just lifted, flattened again. "We generally recommend that young wizards go back no more than one hour.
"Experiencing seven extra hours puts too much strain on you."
She came clacking down the stairs and said worriedly,
"Zhang, I don't know why Dumbledore agreed to let you use the Time-Turner this way, but remember: if you feel unwell,