7.

Lorna was in ecstasies the next day about Vivian's gift for music, and made Vivian promise Diana and Harriet a demonstration. Vivian didn't mention that she had seen a unicorn to anyone, although she relayed the Snape incident to Lorna, Harriet and Diana over breakfast to a chorus of laughter.

"It's obvious what he's doing," said Lorna, "he's trying to catch the heir of Slytherin!" Vivian suddenly knocked over her cup of coffee, but the others were too busy looking solemn to notice. Rumours had been circulating wildly since the attack on Mrs Norris, and people were speculating wildly about who or what the heir of Slytherin actually was.

"No, I know what he's really up to," said Diana, "he's stalking us!"

They laughed, Vivian trying to dismiss the memory of the book she had found in Snape's office and her growing certainty that Snape had been in love with her mother. "Thanks for that," said Harriet, "now I'm really going to sleep soundly!"

"He's so-" began Harriet, but Lorna gave her a vicious nudge: Snape was walking past their table. He gave them a particularly poisonous glare, and passed them in silence.

"Wash your hair, mate." Diana said in a voice too low for Snape to hear. The four of them burst into suppressed laughter. Snape heard them giggling but forced himself not to look round. Honestly, these fifth years were simply impossible, especially the girls. He had always ignored them when he was at Hogwarts, ignored them as they sniggered behind his back, like this bunch were doing now. Only with the Slytherins had he found companionship of a sort. A peculiar, cold kind of fellowship at best, but still better than nothing.

It was a flying lesson first thing, which Vivian was forbidden from taking part in because she was still so weak. In truth, despite the potion she felt somewhat worse than she had done a month ago: sometimes she had dizzy spells even when she had taken the potion, and a couple of times she had been forced to spend the day in bed, afflicted with a blinding headache and nausea.

Harriet, Lorna and Diana left Vivian at the breakfast table, as they had to hurry outside. Vivian decided to linger over her breakfast, as usual the food was excellent, and she wanted to think about what she had seen last night. Why had the unicorn saluted her? And was Snape really trying to catch the heir of Slytherin?

"That would explain why he's hanging around outside our window." She thought. She decided to speak to Snape and explain that she was completely innocent and if necessary could produce alibis. What had started out as rather amusing was becoming serious. Before she had time to consider this further, she was interrupted by a voice:

"Excuse me." It was a second year, Hermione Granger. It was unusual for students to have very close friendships with people in different years, but perhaps because Vivian seemed so shy and young for a fifth year, or because Hermione was so assured for her age, they had become friends after quarrelling over a book they both wanted to borrow from the library.

Vivian smiled up at her.

"Hi." She said, "Sit down."

Hermione perched next to Vivian.

"I'm in a bit of a hurry," she said, glancing nervously at her watch, "I just thought I'd stop and ask you if you had a copy of "Hogwarts: a history" I could borrow."

"Sorry," said Vivian regretfully, "ours is a first edition, so I'm not allowed to take it out of the house."

"A first edition!" Hermione gasped. "You lucky thing!"

"It was my father's." Vivian replied.

"Oh." Said Hermione. She looked suddenly awkward.

"It's alright, he died when I was little."

"I've read about him of course," Hermione said eagerly, "he was a brilliant auror by all accounts."

"Yes, he was." Vivian replied, "But you must be the first person here who's ever heard of him."

Hermione sniffed.

"People here don't read." She answered scornfully; Vivian could tell this was a long-standing complaint.

"I know how you feel." She replied fervently. People had treated her as if she was weird when she produced a battered copy of "Jane Eyre" in the common room.

Hermione looked at her watch again.

"I'm going to be late!" she exclaimed, as if the world was about to end. Before Vivian could say anything else, Hermione leaped to her feet and dashed off, calling a hasty "bye!" over her shoulder as she ran. Vivian hadn't had a chance to ask her what she needed the book for, but she didn't really need to. It was the heir of Slytherin again.

*

Vivian had been prepared to argue her innocence with Snape that evening, but when she arrived she found the office empty, with a smoking goblet lying on the desk. She drank the potion quickly, and shuddered. Was it her imagination, or was the potion beginning to taste worse?

She was used to the gloom of the office by now, even the collection of slimy things in jars seemed rather commonplace; she glanced around her as she prepared to go, and caught sight of the chessboard standing in a corner of the room, still set out from when she and Snape had used it before.

She crossed the room and studied the board. Then she moved the black rook four paces right.

"Check." She murmured softly, and turned to go with a strange feeling of satisfaction.

*

It was quite late; Vivian began to hurry in the direction of the Ravenclaw common room. Strangely enough, she was beginning to feel rather ill. She was walking down the corridor past the transfiguration classroom when she fainted. The walls seemed to dissolve into a brown swirl; dimly she felt conscious that she was falling, but she was unconscious by the time her head smashed into the floor.

*

Snape was marking first year essays when Professor McGonagall rushed in looking distracted.

"It's Vivian Leroux!" she said, before Snape could say anything, "She's fainted."

Snape swore softly to himself, and reluctantly stood up.

"Where is she?" he asked

"Just outside." Professor McGonagall replied. Snape gave her a sharp look. She was obviously upset, he realised with surprise - he had never seen her at such a loss before.

"Sit down," he said, conjuring a cup of tea onto his desk, " you drink that and I'll take her to the hospital wing."

"She's. Bad." Said Professor McGonagall faintly, "Twitching. And her head's bleeding."

Snape hastily climbed the steps and looked around. Vivian was lying on the corridor floor. Her head was bleeding from a cut, he supposed she must have caught it on something as she fell, and her hands were twitching in some kind of spasm. It was an unpleasant enough sight, but Snape didn't flinch. Instead he magicked a stretcher for her, which floated in mid air, and slowly he began steering it towards the hospital wing.

Typical. Trust the girl to faint and interrupt his work. She looked fragile, almost childlike as she lay there unconscious. With her eyes shut he could perceive a faint resemblance to her mother in the delicacy of her bone structure. Snape couldn't find it in himself to pity her. Not much, anyway. She had obviously not taken the potion on time, or something like that. It was clearly her own fault.

Unless.

With a sharp exclamation he seized Vivian's wrist. He could make out a faint symbol traced over the pale skin through which the veins were clearly visible. A figure eight drawn sideways on: the sign for infinity.

"No." he whispered. "No."