There, he stopped.
And then something caught his attention - a huge line of spiders, all making their way out of a crack in one of the windows.
"Strange. I've never seen spiders act like that," he said.
"I don't like spiders," Ron offered, but had little time to dwell on it, as the three of them noticed something else – water on the floor, and a reflection. "What's that?"
Craning his neck, Harry saw something scrawled across the wall in red.
The Chamber of Secrets has been opened, enemies of the heir beware.
"Oh no…" Harry gasped, spotting something else, hanging limply beside the message and moving closer. "It's Filch's cat. It's Mrs Norris…"
By now, he had begun to hear hushed whispers all around him. But it wasn't the same mysterious voice he had been following – it was half of the student body, standing there, staring at him.
"Enemies of the heir beware?" Malfoy scoffed from amongst them, turning to look at Hermione. "You'll be next, mudbloods!"
And then, another figure appeared.
"What's going on here?! Go on, make way, make way!"
Oh no.
Turning slowly on his heel, Harry faced Filch.