Chapter 6: The 3rd Floor Corridor Door
"What do they think they're doing, keeping a thing like that locked up in a school?" said Ron finally. "If any dog needs exercise, that one does." Hermione had got both her breath and her bad temper back again. "You don't use your eyes, any of you, do you?" she snapped. "Didn't you see what it was standing on?" "The floor?" Harry suggested. "I wasn't looking at its feet, I was too busy with its heads." "No, not the floor. It was standing on a trapdoor. It's obviously guarding something."
Harry suddenly went stiff. A thought had just occurred to him, and he didn't like it one bit. "There's another problem, though." "What?" asked Hermione scathingly. "The problem that we almost got killed?" "No, but it's almost as bad. That was the forbidden corridor, right Hermione? If a place is forbidden, you make it so people can't go there." "Obviously." "So the point is, if it's forbidden, why is the security so weak that you – a brilliant first year, but a first year nonetheless – can get past it?"
Hermione's lips had formed a O shape when Harry called her brilliant, but they quickly snapped into a thin line of determination. "We need to tell a teacher." Ron bolted upright. "Are you mad? "Professor McGonagall, we were out of bed at midnight, and we went in the forbidden corridor. If it's forbidden, why could we get in?" Harry shook his head. "We don't say it like that, obviously. How about – yesterday evening we were looking for somewhere quiet to practice Charms, and we found what we thought was an empty classroom, but it was locked, and Hermione used Alohomora, and it turned out we'd accidentally got in the third floor corridor. Then McGonagall knows it was an accident, and nobody knows that we were out of bed when we shouldn't have been. Then we ask about how come Hermione could unlock the door if it's forbidden."
The matter settled, they went to bed. The next day, after Transfiguration, Harry, Ron and Hermione stayed behind to give their story to Professor McGonagall. When they finished stammering it out, she had an expression like thunder on her face, but was quick to reassure them that she was not cross with them, and awarded them seventy-five points for "discovering a serious flaw in the safety protections of the school and reporting it immediately". For the rest of the day, the teachers could be seen going in and out of the third floor corridor. At the evening meal, Professor Dumbledore stood up and announced that the third floor corridor was no longer forbidden.