A/N: This chapter is dedicated to lovely reader and reviewer gr8rockstarrox. Still not here yet, but soon, I hope! Enjoy, everyone. We've reached new levels of drama in Lydia's life, and I'm LOVING it.

-C

It was one of Lydia's bad days. Not to do with work, although she had more classes than usual, plus she had a staff meeting she couldn't avoid that evening. No, the thing that made it a bad day was that she was having an influx of memories she couldn't avoid. The walls of the castle felt suffocating and tight, not to mention those of her own classroom. Her students didn't seem to notice, but Lydia could hardly concentrate on a thing.

It started early that morning. She'd woke suddenly, although not from a nightmare, but with a distinct feeling that someone was in the room who ought not to be. The room was still, though, and she could hear nothing out of place. She even held her breath and waited for a sound or a shift the darkness, but there was nothing.

Severus seemed to notice nothing, and Lydia tried to forget about it as she went through her day. She'd imagined Mary's hanging corpse as she went up to breakfast, which startled her terribly, but Severus had gone on ahead of her, and no one was there to notice. She'd thought Harry was James again for a moment, and a boy in Gryffindor—not a student of hers, mercifully—asked out one of his classmates in front of everyone and was mercilessly turned down. It was all too familiar, and Lydia excused herself from breakfast almost at once.

Things were getting worse. Lydia almost called three different students by their parents' names, and when she looked out at the grounds at a snowball fight, she was sure she'd heard Sirius's bark of laughter.

"Professor," Angelina Johnson said. "How do I find the inversion where there's four reversals?"

Lydia tried to think of where she was and what was happening. She looked down at her student and realized she'd given them a problem set, that Angelina was asking about the problem set.

"That's a very good question," Lydia said. She couldn't remember what the question was; her brain hadn't processed it. "Does anyone think they know how to answer it?"

Cedric and a few of the Ravenclaws raised their hands. Lydia called on the person who spoke the least of the usual bunch, and she listened to the answer to figure out what the question was. The answer was, as far as she could tell, a satisfactory one for the question she discerned was asked, and so she gave it approval and continued to circle the room. Her footsteps on the stone floor were rhythmic, familiar, but not soothing. She thought of exams as a student, of the anxiety of whether she would succeed or fail, of Sirius watching her in Arithmancy class.

Stop, she told herself, and she lingered at her desk, watching the students work from the front of the room.

Most days were not like this. Most days, the past stayed fairly firmly behind the veil, but today it gnawed at her from every corner and crevice. Three times already she was sure someone was nearby when she was quite alone, and routinely she began to wonder whether she was going mad. She tried to focus on one thing at a time, help one student at a time, and when it was time for the students to leave, she was relieved to see the back of them for perhaps the first time since she began teaching. She was ready to steady herself before her next course, but Cedric paused on his way out and waited for the rest of the class to file out before he said, "Professor Rowe, are you not feeling well?"

"Sorry?" she said. She'd barely registered what he said before he clarified.

"You seem very distracted," he said.

"I'm…fine," she said. "Really, I'm quite fine, but I have to prepare for the next class. If you'll excuse me, Cedric."

He hesitated again, but he did leave without pressing the matter. Lydia pressed the back of her neck feeling that it was slick with sweat. She tried to shake this off, although she was not sufficiently hot or cold enough to be sweating. She focused on copying down the problem for her fifth year students, on doing one thing at a time, at ignoring the sensation of being watched. She started running numbers through inversions in her head the moment her next batch of students walked through the door. Up and down, round and round she pushed the numbers. The students seemed to notice nothing unusual, putting their essays and problem sets on her desk before starting on the problem on the board. They worked silently, and Lydia paced the room, wanting to check if she was still sweating but afraid to draw attention in case she had a student as observant as Cedric in this course.

Before she was about to begin the discussion, the door of the classroom swung open, every student turned to look, and there was a general murmur of surprise when Severus stepped in.

"Professor Rowe," he said smoothly, "I apologize for the interruption, but if I might borrow you a moment…?"

Lydia nodded, told the students to share their work with the person next to them and discuss discrepancies, and then she followed Severus into the corridor. She was even more surprised when he swung the door shut again. She was about to ask what he was doing when he started checking her eyes and pulse.

"Sev—"

"Cedric Diggory told me you seemed out of sorts."

"I told him I'm fine—"

"And he did not believe you. And when he described your demeanor, I didn't much believe either. Lydia, you're sweating in January. What have you taken?"

"I haven't taken anything."

"Lydia—"

"I really haven't."

She let him access her memories, and she tried not to fight even when he traced over the paranoia and confusion of her afternoon. When he pulled out of her head, he was staring at her with alarm, which made her more uneasy than irritated.

"What is it?" she whispered.

Severus's frown solidified again, but still he looked more troubled than usual.

"I don't know," he admitted, "but if it's what I think it is, it isn't good."

He urged her to cancel class and go straight to the infirmary, but when he said she wasn't likely in immediate danger, she refused. She finished class, although the whole thing had her increasingly distracted, and then he met her at the infirmary directly after classes. She was surprised to see it was Albus there waiting for them and not Poppy, but Lydia didn't ask, just sat where Severus directed her to.

"This couldn't wait until the staff meeting," Severus said to Albus. "Drink this," he added to Lydia, pressing a vial into her hands.

"It is…?"

"An antidote."

She didn't ask any more. She downed the very thick, sweet potion in one. It was disgusting.

"Indeed," Albus said, sitting in the chair beside the cot she'd been directed to. "And how was the substance transmitted?"

"Someone has tampered with my potions for her sleep," Severus said. His voice was a growl, and Lydia knew he was upset again with himself. Once again, someone had gotten in to hurt her while he slept soundly beside her, and this time they might have killed her.

"But you said I wasn't in immediate danger," Lydia said. "You said I was safe to teach."

"It wasn't poison as such," Severus said. "It was a drug, a mild but long-lasting hallucinogen, something to make you paranoid and drag forward the shadows, so to speak. So whoever did this, they know you have enough ghosts in this building to drive you mad with pain and paranoia within, oh, a couple of days, a week at best."

"And who noticed the change in behavior?" Albus asked.

"Cedric Diggory," Lydia whispered. "He's…he's a very sharp, very observant boy."

She could almost feel her shoulders unknitting. The exhaustion hit next, and she laid down on the cot, exhaling heavily. The room swam a bit at the edges of her field of vision, but otherwise she felt only immense relief.

"He's also a very diligent boy," Severus said. "He didn't just shake off her insistence that she was fine, and he came to me instead. But this cannot keep happening, Albus."

"No, it can't," Albus said softly. "I don't know how the intruder is getting in—"

"We can't lock the door. If someone needed to find me in the night for Head of House duties—"

"Into the castle, Severus."

"I believe the intruder is already in the castle," Severus said darkly. "I believe the intruder has every right to be in the castle."

Lydia shivered again, and Albus rested his hand bracingly on her arm.

"You are referring, I think," Albus whispered, "to your theories."

"Yes."

Lydia closed her eyes and just listened. She wasn't sure if Severus had told Albus that she knew some of his theories, so this would be informative, if nothing else.

For a long time, Albus said nothing, but then he said, "When Lydia was previously attacked, was the person in question at the school?"

Severus hesitated. Lydia wasn't even sure. Was that the year Quirinus had been in the job previously, or was it before that? The timeline of her nightmares was so blurred, she couldn't keep track anymore.

"It may have been that year," Severus whispered.

"But it may not have been," Albus said. "I trust you have records, Severus. From the development of her potion. I trust you kept records on that."

"Yes."

"Check them. If you have reason to suspect it, then bring it forward. But it also doesn't line up with your theory, you understand, of this person being corrupted abroad. If they were already assaulting one of our teachers, then it would follow that they were already corrupt."

"Corrupt or not corrupt," Lydia said, sitting up despite the way the room spun, "I don't think this was Quirinus."

Albus raised an eyebrow but said nothing about her knowing the theory. Perhaps he suspected she'd been told, or perhaps he didn't want her to know he didn't know. Severus's jaw twitched, but Lydia pressed on.

"He seemed to genuinely like me before," Lydia said. "And even now…he's not exactly sneaky, is he? I can't imagine he'd manage to sneak into Severus's quarters without being detected."

"Don't underestimate people, Lydia," Severus whispered. "That's the kind of thing that can get you killed."

She wondered if he was referring to Sirius, or if he really thought she underestimated Quirrell, but she wanted to remind him they weren't at war anymore. She was about to when Albus raised a hand between them and said, "We will consider all possible options, including Quirinus. I am inclined to agree with Lydia on the point, if not necessarily on the details. But that remains that if it is not Quirinus who has attacked her, then it is someone else, and that is perhaps more troubling. If it is someone else who, as Severus says, has every right to be at Hogwarts, we need to determine who and why. And if it is worse, someone intruding from outside Hogwarts, then we need also determine how. I suggest you rest before the staff meeting, Lydia. I trust she will be well enough to attend?"

"Yes," Severus and Lydia chorused. Severus would have rolled his eyes if he were anyone else, but he simple stared at her with frustration.

"Then I will see you both shortly. Poppy will return after the meeting. She says she has no reason to be back before then."

When Albus left, Severus and Lydia sat in silence. They really had no theories to discuss, and Lydia was trying to keep steady, normal breathing to bring the room into focus faster.

"Thank you," she whispered, when she was well enough to sit up.

"For what?"

"For fixing it," she said, grasping his hand. "Even when I was stubborn."

"Lydia," he said, "you are always stubborn." He kissed her forehead. "It has never stopped me before."

They sat in silence as long as they could before they had to go down to the staff meeting. Severus held Lydia's hand most of the way, not in any romantic sense, but because he was still concerned that she might keel over at any time. Their usual spots were open, Severus beside Minerva, Lydia beside Quirinus. He smelled strongly of garlic, and she felt incredibly uncomfortable. She realized Severus's suspicions were starting to get inside her head, even if she didn't fully believe them.

No one seemed to notice that anything unusual had happened with Lydia. Albus and Severus were keeping her poisoning very quiet, which she supposed was a good thing. On the bizarre off-chance that it was one of the teachers trying to kill her, they wouldn't want her attacker to know that they were aware someone was coming for her. Or, she thought it seemed sensible, with her very limited knowledge of covert operations, gleaned mostly from the Muggle films of her childhood.

Each of the teachers gave their reports in turn. Lydia marveled at how easily Severus could seem unconcerned and bored, especially given how concerned she knew he was. She supposed one learned a thing or two in a war, especially in the service of a maniac. But then, Lydia knew he'd begun his education in deception many years prior, as the unwilling prisoner of a different kind of maniac. She recalled briefly the once-familiar sight of Tobias Snape attacking his wife, in relief on the curtains.

"Lydia?" Albus said.

She pulled out of her reverie so suddenly, she was worried she might seem unwell still. She cleared her throat.

"The students are on track," she said. "Better than on track, for some of my groups. The third year students in particular are very self-directed. Cedric Diggory set up a post-run study system for the holidays, so they never seem to take a break. Even if it's yet to be put to a real content test, it's given confidence to some of my shyest students, and class camaraderie and participation are at an all-time high."

"That's excellent to hear," Pomona said, beaming. "I think Cedric will make an excellent candidate for Prefect, when the time comes."

"I quite agree," Lydia said, smiling. "Otherwise…" She hesitated. "Nothing to report."

Albus inclined his head, and something she didn't know how to categorize flashed in his eyes. He turned to Quirinus, who gave his stuttering report of the progress through Creatures that the third year students had been making. It was painful to listen to on the best of days, this stuttering when he used to be so well-spoken. But now that Lydia had Severus's ideas in her head, it was unnerving.

Was it underestimating him to think he couldn't sneak up on them, as shuddering and halting as he'd become? She didn't think so, but people always could surprise you. Peter Pettigrew had never seemed a particularly stealthy sort, but in many ways, he'd been the stealthiest of all the Marauders: easy to overlook, quiet, unassuming. No one would expect that he had hearing that could rival the rest of them (including Remus), or that he had the uncanny ability to suddenly just be at your side, and you didn't remember him being anywhere near before. Down to the map, Lydia supposed, but still.

"All the protections are in place," Albus said. "Now that we have Quirinus's guard troll, every chamber is guarded well, and I have recently moved the final protection into place."

There was a small murmur of approval or interest, but Lydia didn't care what was guarding the Philosopher's Stone. She was just glad she wasn't personally responsible for its safety. She was a little busy worrying about her own safety.

They were released from the staff meeting, and Lydia was ready to leave, but Severus put a firm hand on her knee, so she stayed seated. Most of the teachers trickled out slowly, and she was surprised to see Albus going to the kettle and preparing a few cups of tea. Quirinus was the first to leave, and others trickled out after him, but Severus kept his hand on Lydia's knee until they were alone with Albus and a cup of tea had been set in front of each of them. Lydia's was not cooled, but she was grateful for that. She let the steam curl up to greet her nose, and she didn't look at either man.

"You did very well," Albus said softly.

"I was distracted," Lydia said.

"That's a good thing," Severus said. "The person who did it does not expect you to be aware you were poisoned. Mild distraction could be a symptom of the drug, either wearing off or in too small of a dose, depending on when in the night he drugged you."

"Are we sure it's a man?" Lydia asked. "Isn't poison usually done by women?"

"Yes, but strangulation is typically men. It takes a great deal of strength to strangle someone, even while they sleep."

"They didn't succeed."

"Even so."

"And the hands were significantly smaller than yours—"

"I believe Severus is correct in this, Lydia," Albus whispered. "Hands come in many shapes and sizes, but I believe the poisoning could signal less about gender and more about the frame of mind of the attacker. Desperation, perhaps, or a kind of fear."

A fear of Severus, obviously, because no one would ever be afraid of her. She supposed if the attacker knew Severus was no longer taking his own sleeping potions, there was a reason to be afraid, to want to be in and out much quicker.

"What should I do?" she asked.

"Keep doing what you've done," Albus said. "Severus and I will do the rest." She began to pout a bit, but Albus smiled and said, "It is not a question of your ability to be helpful, Lydia, but more a need to not alarm the attacker. If you go on as you have done, we can draw them into a mistake more easily than if you are increasingly cautious."

Lydia didn't love the idea of being a kind of bait for Albus's purposes again, but at least this time she knew about it in advance, and Severus was protecting her actively. She agreed reluctantly to do nothing, and she and Severus stayed in the staff room until she finished her tea, even though it meant a late night. He didn't seem to want to rush her, and for that she was relieved.

A/N: So, someone is drugging Lydia, Cedric is an observant boy, and Severus is convinced her attacker is Quirrell, while Albus and Lydia aren't so sure. Things are getting tense! I'm still drafting the summer between the first two books, and I'm really enjoying ratcheting up the tension and conversations. Which kind of tension? I guess y'all will find out!

Review Prompt: As Cedric is obviously one of Lydia's prize students, how do you think she's going to feel during book four, with two of her favorite people competing in the Triwizard Tournament? There's something to chew on for the post-Sirius-reveal.

-C