Professor Caset, Head of Hufflepuff, sat calmly in Dumbledore's office, sharing a bottle of butterbeer with his host.
"I know you feel protective towards the girl, Albus, but you must consider the possibility."
"She would never do something like this, Robert. I am sure."
"But her family, Albus?"
"She is not her family," Dumbledore said, frustration showing in his voice.
"She watched the dementors overrun her family home, Albus, watched her father's soul ripped from his body. And I'm afraid she blames you for that. I've seen how she avoids you now."
"And I blame myself," said Dumbledore quietly, "But she deserves our sympathy."
"And if the stress and trauma has driven her to darkness?" demanded Caset, "Don't by petrified students deserve sympathy too? And protection?"
"She has a good heart."
"She is unstable," Caset replied bluntly, "And with her power that could make her dangerous. You know how powerful the McGonagall's are, Albus – the wandless powers they have. And I have seen her sneaking books from the restricted section of the library. And the girl not only had a prohibited pet, but she killed it rather than hand it over."
"The animal's death was an accident. She was distressed…"
"And if she becomes distressed with a fellow student? Or with you?"
Dumbledore shook his head.
"Remember my prophecy."
"What is wrong with you, Robert? Why can't you show a little loyalty to a vulnerable student?"
"I'm sorry, Albus, but my loyalty is to you and to the rest of the students. It has to be."
Two days later Minerva was making a last dash back from the library to Gryffindor tower, an advanced book on animagi tucked under her arm, when she saw Tom Riddle standing on one of the staircases, gazing mournfully into the vast depths of the castle.
"Tom," she called, "Is everything okay?"
He looked up suddenly, "Fine." He said.
"Seriously?"
Another one of his shrugs.
"Tom?"
"I heard the teachers talking," he said finally, not looking at her.
"About what?"
"The Chamber of Secrets. There's been another attack."
"Oh no. When? Who?"
"Tonight. Professor Vert – petrified."
"But Professor Vert was working on the mandrakes to restore everyone."
"Well someone else is going to have to do that now. And the teachers, they were talking about closing Hogwarts. Sending everyone home."
"Closing Hogwarts?"
Tom nodded. "Hogwarts is my home, Minerva," he said suddenly, "What happens to me if it closes?"
She stared at him, and felt a tug of sympathy. "It's mine too." She said, "Since my parents – you know…"
He nodded.
"But you could still go back to your family home couldn't you." He said resentfully, "With your brothers."
"No," she answered, suddenly amazed that she was going to tell someone the truth, and even more surprised that it was going to be a Slytherin – Tom Riddle. But Tom was changed from the creepy first year he'd once been. He was calmer, more controlled than almost any other student from his house.
"I can't ever go home." She told him. "My father disowned me right before the – you know. We're an old family, old magic, disowning matters. I'm permanently banished from my home and I have nothing but my robes and my books. Essentially, once I leave Hogwarts I'm on my own."
"Oh," he said. She was glad of his reaction. Dumbledore would have been suffocatingly sympathetic and she couldn't have borne that. Tom's simple, emotionless responses suited her better these days.
"So I really don't want it to close either," she continued.
"I just wish there was something we could do," Tom said.
"Maybe there is," Minerva murmured.
"What?"
"We have to work out whose doing this."
"Seriously?"
"Seriously. You're a Slytherin – you should have a head start in the detecting."
"You just assume it's a Slytherin."
"Well the Chamber of Secrets was Salazar Slytherin's thing. Professor Binns told me. Makes sense for it to be a Slytherin."
"Could be a reckless Gryffindor," he countered. "All courage and no brains. Professor Caset thinks it's you."
She pretended to be offended, "Plenty of brains, thank you very much. Youngest O in a transfiguration NEWT ever and…" she waved the book under his nose, "An animagus."
"No." For a second he looked genuinely impressed.
She raised her eyebrows and, after a quick glance around, dropped the book, and then transformed into a cat and back again.
"Impressive," he told her.
"Coming from you, that's quite a compliment," she said, "But don't tell anyone – I haven't registered yet."
"Well that could be useful," he said slowly, "Perfect disguise for wandering the school at night…"
"…looking for monsters." She smiled nervously. "So are you in?"
"I think so," he said slowly. "What's the plan?"
"Catch the culprit, find the monster, save the school. Oh – and get rid of the dementors."
"Deal." His smirk returned. "Look at this – a Slytherin and a Gryffindor working together."
"Desperate times," she answered, her expression matching her words.
"Aren't they?" he agreed.
For the next few nights Minerva and Tom patrolled the corridors. It was easier for Minerva, she could transform into a cat. It was harder for Tom, he had to sneak around and avoid anywhere near the patrolling teachers.