The next day Minerva was stumbling along a corridor when she caught sight of a dementor approaching from the other direction. Quickly she turned back the way she had come. She began to walk faster and faster. She broke into a run. It was a mistake, of course. You can't outrun a dementor. Running only helps it to sense your weakness, your fear. The dementor pursued her. She felt it getting closer. She ran faster. The dementor increased its speed behind. Now she was hearing whispers around her.

"It's chasing her!"

"Do you think it's her?"

"She's opened the Chamber?"

"She is from an old Slytherin family."

"And there's a prophecy that she's going to kill Dumbledore."

"It can't be her, can it?"

"Why else would it chase her?"

"Have you seen the dementors chase anyone else?"

Now Minerva was panicking. Running faster and faster. The dementor right behind, the whispers surrounding her. The memories starting to drift into her mind. Soon she wouldn't be able to stop them. Soon the dementor would be too close. Why was nobody helping her, she thought desperately. Why was she always alone?

She turned a corner, into an almost empty corridor, just one student in it. She raced past him, the dementors closing in, when suddenly she heard it.

"Expecto patronum!" Loud and confident.

She ran a few more steps and felt the closeness of the dementor fading. She turned to see the silvery snake encircling the dementors and pulling them back down the corridor, away from her and her memories.

She gave a sigh of relief and suddenly her legs felt weak. She leant back against the wall and let herself slide down it into a crouching position, gasping for breath.

Finally she looked up at the boy who was standing in front of her.

"Thanks," she said weakly, reaching in her pockets for some of the chocolate she always carried now.

He shrugged, "Always good to have the opportunity to show what I can do."

She rolled her eyes at his arrogance, and sat up straighter, determined not to look weak in front of a Slytherin. "Happy to oblige," she said dryly, "I notice your patronus is a snake. Can you get more Slytherin?"

"Whereas yours is a lion, I suppose?" he asked, sitting beside her.

"Wearing a red cape and brandishing a sword." She assured him, feigning a great deal more confidence than she felt, and offering a piece of the chocolate.

He smirked as he took the chocolate.

"Tom Riddle," he said, holding out his hand.

"I know," she replied, shaking it. "Minerva McGonagall."

"I know," he replied, smirking again.

They sat in silence eating their chocolate for a moment.

"So why do you think they were chasing you?" he asked.

"They sense weakness," she answered.

"From what I hear, you're not weak," he told her. "Didn't you already get an O in your transfiguration NEWT a year early? And straight Os in your OWLS, which you're apparently going to repeat in the rest of your NEWTS at the end of this year?"

She returned his smirk, "Careful," she warned, "You're in danger of complimenting a Gryffindor."

"I won't tell if you don't."

She broke off another piece of chocolate and popped in her mouth.

"So," he persisted, "Why do you really think they're after you?"

They were outside the Defence Against the Dark Arts classroom. She got to her feet and wandered inside, signalling for him to follow. Once in she waved her wand at a cabinet and it flew open.

"Boggart." She said.

Out flew a dementor, straight towards her. Minerva took a deep breath, grasped her wand and shouted "Ridikulus."

The dementor began to spin rapidly as though being sucked down a plughole. Minerva turned to Tom.

"See," she said, her face solemn, "Weakness. Dementors are my weakness."

Tom nodded his understanding. The boggart had moved sideways and was now in his eyeline and transformed rapidly.

"I am the most powerful wizard of all time!" proclaimed Grindelwald.

Minerva turned to stare at Tom's boggart as he shouted "Ridikulus" and Grindelwald suddenly found himself with the body of a horse and no way to hold his wand.

Together Minerva and Tom forced the boggart back into the cupboard and locked the door. She turned to look at him.

"Grindelwald?" she asked.

He shrugged.

"I'm impressed." She told him honestly.

He gave another one of his smirks, "That sounds like a Gryffindor complimenting a Slytherin," he said.

"I won't tell if you don't," she echoed teasingly.

They looked at each other for a moment, and then left the classroom and headed off in different directions.