Written for Healer Pomfrey's February Challenge; required elements were Snape and McGonagall, concealment charms, and the non-canon magical illness of Grindylow Pox. The story was supposed to be a one-shot, but that didn't work out as I expected, so this is the first chapter with more to follow. Not my usual style, but I hope you enjoy it nonetheless.

Disclaimer: Written out of my deep affection for the characters and settings of JKR's world; everything is the property of JKR and no infringement is intended.

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"You have thirty minutes to make your best attempt at brewing a Shrinking Solution, although I don't hold out much hope for the results. Your instructions are on the board. Begin."

Snape watched as the students immediately bent their heads to their work, the only sound in the classroom that of daisy roots being chopped. His mind was elsewhere and he winced as his tongue automatically went to the alveolar ridge just behind his upper teeth where a largish, tender bump had been distracting him all day. He was acutely aware of it every time he spoke, and as the tip of his tongue drifted back to his hard palate, he discovered two new tender areas which had recently developed. He didn't remember burning his mouth or consuming anything irritating during the course of the day, but it was the first week of a new term, and anything could have happened. He shook his head impatiently. He couldn't allow himself to be absent-minded while there was an entire classroom full of dunderheads just waiting to blow up his classroom.

Snape paced the rows of tables, stopping occasionally to snarl reminders at forgetful students who were being too liberal with the rat spleens and leech juice. When he reached the back of the classroom, he spun on his heel, allowing his robes to flow out behind him, but the dramatic effect was lessened somewhat when he lost his balance and had to catch himself against a nearby table. That was odd, too. He didn't feel ill exactly, just a bit lightheaded and not quite himself. Tired, perhaps, but nothing a quiet weekend wouldn't put to rights.

---

By the end of his final class of the day, Snape knew he had crossed the border from feeling not quite himself to feeling decidedly ill. Even when a careless second-year reduced his cauldron and a portion of the worktable to a smoking, gelatinous mass, Snape lacked the strength to do anything about it other than ordering everyone to clear out while he dealt with the mess. Afterward he dragged himself to his quarters, his head aching, the simple act of walking causing the pounding discomfort to intensify with each step. The inside of his mouth was now completely covered with sores, and as far as he could tell, his throat was also affected because swallowing was becoming extraordinarily painful.

When he reached his rooms, he went directly to his bed chamber. Standing in from of the mirror, he murmured "Lumos," and after a bit of awkward maneuvering, was able to use the wand light to catch a glimpse of his throat, the sight of which made his eyes widen in surprise. It was covered in angry, greenish-red sores. No wonder it hurt to speak and swallow...even breathing was becoming uncomfortable. He tucked his wand away, feeling very cold and shivery.

What could possibly be ailing him? He hadn't been around the students long enough to pick anything up, and besides, it didn't feel like a cold or even the flu for that matter. He cast a longing look at his bed, where the blankets were rumpled invitingly. More than anything he wanted to rest, but he was expected in the Great Hall for the evening meal and at a staff meeting immediately afterward and while he might be able to skip the meal, the meeting was mandatory. He wasn't terribly hungry, but he would need some kind of sustenance to endure the meeting. He only hoped there was something remotely palatable that wouldn't irritate his throat too much.

---

After a nap that did nothing to make him feel better and a hastily-applied concealment charm to hide the worst of his physical deterioration, Snape made his way to the Great Hall, taking the empty seat next to Minerva.

"You're having custard?" he asked, averting his gaze from the pale, lumpy substance she was listlessly pushing around the bowl. "Is that all? No saucer of cream?"

"Stop it, please," Professor McGonagall said, giving him a haggard look. "It's been an exceedingly long day and I'm in no mood for any banter at the moment."

"Surprisingly enough, neither am I," he said, using both hands to heft a nearby teapot. He almost managed to keep his hands from shaking as he held it out towards her. "More tea?"

"Thank you," she said quickly, with a brittle smile that did not quite touch her eyes. She added an unusually copious amount of honey to her cup and then wrapped both hands tightly around it as if trying to absorb the warmth. He studied her as he took a tentative sip of his own tea. Was she ill, too? She looked well enough, but he certainly wasn't the only staff member who was handy with concealment charms.

A sudden searing pain in his ear interrupted his thoughts and he quickly replaced his cup on the table, inhaling sharply and pressing his hand to the side of his head. The room seemed to tilt briefly before righting itself once again, and he closed his eyes, fighting off a wave of dizziness. He concentrated on taking careful, slow breaths until the pain eased and the spinning sensation slowed.

After a few moments, when he felt a bit better, Snape opened his eyes to find Madam Pomfrey giving him a searching look. She was leaning forward in her chair, studying him intently, her brows drawn together in concern. He knew that expression well. It promised nosy inquiries into his health and well-intentioned meddling, neither of which he had the patience for tonight. He offered Poppy what he knew was a sickly and unconvincing smile, and even from a few tablelengths away he heard her snort of disbelief. Minerva was studiously ignoring them both.

---

The next morning, sitting slumped in the staff viewing box at the Quidditch pitch, Snape was feeling no satisfaction about Slytherin's win over Ravenclaw; only a profound sense of relief that the match was finally over. Now he could return to his rooms where it was warm and comfortable.

The Ravenclaw students were hotly contesting the narrow Slytherin victory and their loud, angry voices, overlaid with resounding cheers from the Slytherin side of the pitch, were making him feel disoriented and slightly giddy. He accepted Professor Flitwick's congratulatory handshake in a distracted manner. Concealment charms, even skillfully-applied concealment charms, could do nothing for the malaise and fever and body aches accompanying this illness, whatever it was, and he needed to leave before his behavior betrayed him.

"If you'll excuse me," he said to no one in particular, rising abruptly. He was surprised to see Professor McGonagall, who had been sitting quietly nearby, struggle to her feet as well.

"Oh, no you don't," she said, following him from the box. "We have a few things to settle, Professor Snape." He looked to her for an explanation. What possible grievance could she have? It wasn't her precious Gryffindors who had been bested, after all. She shook her head and motioned him toward the stairs.

Snape gripped the rail tightly as they descended from the box. It was taking all his concentration not to trip and fall headlong, and he gave a great sigh of relief when at last he found himself on relatively stable ground.

"You're ill," Minerva said with no preamble, as she caught up to him.

"Whatever gave you that idea?" He tried to speak casually, but was forced to reach out one hand to steady himself as he felt the ground shifting beneath his feet.

She gave him a disbelieving look, one eyebrow raised. "Because I suspect that underneath your appearance of rosy good health, you feel as wretched as I do."

He glanced up briefly to where a group of students were peering over the edge of the viewing platform, perhaps hoping to see a duel. He sighed in resignation and looked back to Minerva.

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

"Agreed."

He offered his arm to her. "Shall we return to the castle before the hordes descend?" Minerva hesitated for a moment, finally tucking her hand into the crook of his elbow. Before they set out, he acknowledged the disappointed booing from above with a lazy wave.

They walked along the path in silence for a few minutes before Minerva offered, "It's the damnedest thing, Severus. For the life of me, I cannot figure out what's making me feel so ill. I have the most dreadful little sores in my mouth and down my throat..."

"Have you been to see Poppy, by any chance?"

Minerva scoffed. "To have her poke and prod and wave her wand at me? No, thank you. A few days' rest and I'll be right as rain."

Snape nodded. He was no more eager than Minerva to have Poppy fussing and fretting over him. "Pepperup was useless for me," he said, the thought of Poppy jogging his memory.

"For me as well," she agreed.

"But if you think a fever draught would help," he said, holding the side entrance door open for her, "I have a few left in my stores."

As Minerva smiled and opened her mouth to reply, a familiar voice from behind them asked, "Now why would either of you need a fever draught?" They froze in horror, staring mutely at one another as Madam Pomfrey stepped between them. "Unless you're hiding something from me?"

Snape was the first to recover his composure. "Don't be ridiculous, Poppy."

"Ridiculous, am I?" she asked, her eyes narrowing, a dangerous edge creeping into her voice. Then in a more casual tone she said, "So, tell me, Severus. How badly were your Slytherins routed this time?"

"I'll have you know," he said, shooting an irritated glance at Minerva who was shaking with suppressed laughter beside him, "that Slytherin won their match today."

She smiled benignly. "Did they? Will wonders never cease? I suppose next you'll tell me you feel perfectly well and aren't trying to hide anything under a concealment charm. But then," she said, withdrawing her wand, "That would be ridiculous, wouldn't it, Severus?"

"I have no time for this foolishness," he muttered,

"Indulge me," Poppy said. As she made a quick sideways slashing movement with her wand, the air around Severus and Minerva seemed to shimmer for a moment as the concealment charms fell away.

Severus stole a quick sideways glance at Minerva. She was pale and sweating, with spots of color high in her cheeks, a greenish-red rash surrounding her nose and mouth. He knew, from the expression on her face when she reluctantly raised her eyes to his, that he looked no better.

Poppy winced as she took in their appearances. "I would be hard-pressed to say who looks worse at the moment," she said, shaking her head. "How long have you been feeling ill?"

Snape ignored her question. "You had no right to remove those charms, Poppy," he protested weakly.

"I wouldn't have had the strength to hold it much longer either way," Minerva said.

"That's beside the point," he began to say, but then stopped. Minerva was right.

Poppy folded her arms. "You are both to go to the infirmary immediately and wait for me in the private ward, just in case you're contagious. And for heaven's sake, lie down until I get there. You look as though you're barely staying on your feet."