Filch paced back and forth along the corridor three or four times, frightening the two of them into hiding in a corner, hardly daring to breathe.
At last, they heard Filch heading upstairs, swearing under his breath.
Only after Filch had been gone for quite a while did they dare relax.
Harry stared at the huge lock before him, unwilling to give up.
But with no other choice, the two prepared to head back.
Ron sighed. "I knew it wouldn't be that simple. The professors' challenges won't be easy every time, especially with all the ideas Professor Holmes has.
"We'd better go back and have Hermione make you another plan... yes, make you a plan!"
Harry felt a flash of inspiration and hurriedly asked,
"Did you just say Professor Holmes?"
Ron gave Harry a strange look and said impatiently,
"Of course I meant him. Hasn't he been running this whole thing all along...?"
Harry's dejection vanished at once, and he said excitedly,
"Ron, I've just thought of a way to open this huge lock. Wood told us about his first practical Defense Against Dark Magic lesson... we need a big axe now. Yes, a big axe..."
Ron watched Harry muttering away. He certainly hadn't heard Wood's story, but he still reminded him,
"Harry, don't forget we're wizards. Remember the Reductor Curse?"
Harry shook his head. "Magic won't work. According to Wood, Professor Holmes likes using Muggle thinking in the magical world..."
Ron rubbed his nose and raised a question.
"Where are we going to find an axe, then? And don't say Transfiguration. I reckon only Hermione could conjure up an axe that big..."
Harry pointed at a suit of armor beside a torch ahead of them and said smugly,
"Isn't there a big axe right there?"
So they crept over