"He's gone?" said Harry frantically. "Now?"

"Professor Dumbledore is a very great wizard, Potter, he has many demands on his time - "But this is important."

"Something you have to say is more important than the Ministry of Magic, Potter.

"Look," said Harry, throwing caution to the winds, "Professor — it's about the Sorcerer's tone —"

Whatever Professor McGonagall had expected, it wasn't that. The books she was carrying tumbled out of her arms, but she didn't pick them up.

"How do you know —?" she spluttered.

"Professor, I think — I know — that Sn- that someone's going to try and steal the Stone. I've got to talk to Professor Dumbledore."

She eyed him with a mixture of shock and suspicion. "Professor Dumbledore will be back tomorrow," she said finally. I don't know how you found out about the Stone, but rest assured, no one can possibly steal it, it's too well protected."

"But Professor —" "Potter, I know what I'm talking about," she said shortly. She bent down and gathered up the fallen books. I suggest you all go back outside and enjoy the sunshine."

But they didn't. "It's tonight," said Harry, once he was sure Professor McGonagall was out of earshot. "Snape's going through the trapdoor tonight. He's found out everything he needs, and now he's got Dumbledore out of the way. He sent that note, I bet the Ministry of Magic will get a real shock when Dumbledore turns up."