The following morning Minerva awoke early and slipped out of the Gryffindor tower and away towards the library, her visctepidus clutched to her heart. In her hand she carried a book entitled 'Basic Principles of Animagi', which she had now completed reading.

As she turned a corner she suddenly saw a figure lying on the floor in the darkness. She approached the person cautiously, calling softly, "Hello? … Are you okay?"

As she got closer she recognised the figure as Mary North, a fourth year girl from Gryffindor.

"Mary," she whispered, bending down to the girl. She was unconscious, but her eyes were still open and staring blankly. "Mary!" Louder this time.

There was no response.

Minerva shook the girl gently, "MARY!"

Still no response.

She stood and looked around her desperately.

And then she heard footsteps and saw Professor Slughorn, head of Slytherin House approaching.

"Professor," she exclaimed desperately, "Something has happened to Mary."

Slughorn hurried over and bent down to look at the girl. When he stood back up there was a concerned expression on his face. He flicked his wand and a beam of light shot from it and away down the corridor.

"Do you know what happened here, Miss McGonagall?" he asked cautiously.

"No, Sir," she replied anxiously. "I was just on my way to the library and I found her. What is it, Sir? It's not normal magic is it? It's something worse."

"We don't know anything yet," Slughorn said in a voice that was falsely hearty. "No need to be worrying, probably just some foolish prank. I'm sure she'll be right as rain in no time."

Minerva looked at him doubtfully, but thought it better to say nothing. Slughorn glanced at the book in her hand.

"Animagi?" he said, "Well, that's very impressive, Miss McGonagall. It is a shame you haven't been along to the Slug club in a long time – you'd be very welcome."

"I don't particularly enjoy socialising anymore, Professor," she replied, her eyes drifting back to Mary.

"Well, of course," Slughorn smiled patronisingly, "Very difficult time you've had lately. Now why don't you head back to the staircases and find another route to the library. Nothing to worry about here."

Minerva looked down at Mary again. This didn't feel like nothing to worry about. Still, she nodded and walked back the way she had come, stopping as soon as she turned the corner and standing against the wall, listening intently to the sound of approaching footsteps rushing down the corridor.

"Horace," exclaimed Professor Dippet as he and Professor Caset reached Slughorn, "What has happened?"

"Petrified, I'd say."

"Petrified!" exclaimed Dippet. "Did you see anyone here?"

"Only the McGonagall girl," Slughorn replied, "She was standing over the girl, called me over and told me something had happened."

"McGonagall," said Caset suddenly. "I suppose we mustn't jump to conclusions, but still..."

Dippet dismissed this with an impatient wave of his hand, "Enough, Robert. Horace, please take Mary to the hospital wing. I need to think."

As Slughorn and Caset headed with poor Mary, Minerva returned to the library, mulling over what she had just heard as she walked.

Two days later and there were whispers all around the school. Three more people petrified and rumours of a monster on the loose.

The students were summoned to the Great Hall and Professor Dippet stood in front of them, his solemn expression matched by the faces of the teachers sitting behind him.

"As you may know," he began, "In the past three days, four students have been taken to the hospital wing in a state of unconsciousness. We believe that all four have been 'petrified'. I must reassure you, that they can all be cured from their current state and will all be cured as soon as the treatment is prepared. I also want to reassure that we are doing everything we can to identify the cause, and to ensure that nobody else is petrified. It is likely that some creature, currently present in the school, is responsible for what has been happening. All of the staff are working hard to identify this creature and to banish it from our school. However to aid us in our efforts, and to ensure that students are kept safe, there will be some changes to school rules.

Firstly, there will be a curfew. All students should be in their house common rooms or dormitories from 7pm until 7am. Any student breaking this curfew will be risking not only detention, but their own safety.

Secondly, we would ask students not to walk the corridors alone. Try to always be in the company of friends, or else ask a prefect or teacher to walk with you between classes.

Thirdly, there will be a strict enforcement of school rules relating to pets. As you know, school rules state that students are only allowed a cat, toad, rat or owl. Any pets of any other species must leave the castle.

If anyone has any information regarding the attacks that have taken place, they should immediately report this to myself, or another teacher."

Dippet paused, and his expression softened slightly. "I won't tell you that this is not a serious situation," he said, "But I believe that if we all work together, as a united school, we can find the creature and ensure the safety of everyone in Hogwarts."

As soon as he finished speaking the Hall was filled with noise as students discussed what they had just heard. Minerva didn't join in. She looked down at her bag, and at the visctepidus contained within it and bit her lip nervously.

Later that same afternoon, Minerva was again wandering the corridors alone, despite Dippet's warning, when she saw two prone figures in the corridor ahead of her. Hurrying closer she found two more victims lay petrified. Beside them lay a dead rat, the pet of one of the two victims. The rat had been cut open and across the wall, scrawled in its blood, were the words: The Chamber of Secrets is open.

Minerva stared at the words in shocked silence for a moment, before turning and dashing down the corridor, seeking a teacher. She almost immediately collided with Professor Caset, head of Hufflepuff, as she turned a corner.

"Professor – two more – petrified," she pointed back in the direction she had come.

Professor Caset raced down the corridor, suddenly followed by a surge of students who had been close enough to overhear. The noise of their exclamations and panicked discussions alerted others, both students and staff, and soon it seemed that the entire population of the school was gathered in the corridor. Minerva could hear the student's voices whispering all around her.

"Two of them. Two petrified! So much for not walking the corridors alone."

"Look at that writing. No creature wrote that. Someone did this. A person did this."

"The Chamber of Secrets – wasn't that created by Slytherin?"

"There's a murderer in the school!"

"No there isn't – nobody's been murdered."

"Not yet..."

In front of the students Dippet, Dumbledore and three other teachers were now staring at the wall.

Dippet turned suddenly, "Everyone," he said, raising his hands and gesturing for quiet, "Everyone, is to return to their common rooms at once!"

Students began to head off to their common rooms still muttering to each other…

McGonagall paused the memory, her eyes on Ginny Weasley, whom Molly was gently hugging and murmuring to.

"Are you okay, Miss Weasley?" McGonagall asked softly.

Ginny met her Head of House's eyes and nodded her head bravely, a defiant expression on her face, despite the tears wet in her eyes.

Dumbledore smiled gently, "If you want to leave the room until this bit is done, it's okay," he murmured. "I promise we will call you straight back in and won't let you miss anymore of the story."

Ginny shook her head. "I want to stay." She insisted.

"Ginny," Molly said, gently reaching out to her daughter.

"I want to stay." Ginny spoke more firmly.

"Then you shall," said Dumbledore, the solemn finality of his words preventing any further objections from Molly.

McGonagall looked at him and he nodded slightly. She gave a more definite nod and resumed the tale.