My thanks to MissDaisy1 for giving this a once-over and to my dear friend and PhoenixSong beta JenAdamson for doing what she does best.
It was a bitterly cold night in what was turning out to be one of the worst winters in recent memory, and Filius, after spending the past several hours marking essays on Concealment and Disguise Charms, was ready to turn in. After scooping hot coals into his bed-warmer and sliding it under the duvet, he'd banked the fire that burned in his grate and extinguished all but one of the lamps that illuminated his small but cozy bachelor's suite. With the remaining lamp in his hand and a leather-bound copy of Dumas' Le ma”tre d'armes (a family heirloom; his great-grandfather had been an early patron of the author) in the pocket of his dressing-gown, Filius padded into his bedroom. He'd set the lamp on the bedside table and was about to ascend the small stepladder beside his bed when he heard the most piteous cry.
"My goodness!" he exclaimed. "That sounded like a cat!" He bent down, thinking the cat -- if indeed it was a cat -- was cowering under his bed, but didn't see anything other than an orphaned sock. "Hm. Must have imagined it." He turned back to his bed and began to climb up on it.
When the cry came again, it was louder, and accompanied by a vigorous rattling at the window that looked out on the Whomping Willow. Filius toppled off the edge of his bed with an undignified, "Ouch!"
"What on earth?" he muttered as he got to his feet, rubbing his sore bum, and peered toward the window. Through the gloom of his suite and the darkness outside, he could barely make out a distinctly feline shape pacing back and forth along the narrow ledge outside, stopping every now and then to bump at the glass with its head and cry for admittance.
"You poor thing!" he said, even though he knew the cat couldn't hear him, and hastened over to unlatch the window, inviting the cat and a blast of icy air inside. The cat brushed past him, leapt to the floor and darted into the next room while he struggled to close the window.
When he went to greet his unexpected guest, Filius was astonished to see who it was. "Minerva!"
Minerva McGonagall lay sprawled inelegantly on the floor, her tartan robes drenched and torn, her hair in disarray, her spectacles askew, panting as though she'd just run a marathon. Filius rushed to her side. "Gracious me, Minerva, what's happened?"
Groaning, she managed to push her upper body off the floor and make a feeble attempt to brush her hair out of her face. "Someone... let a dog... on the castle grounds," she said breathlessly. "Big... black brute... of a beast." She tried to rise, but suddenly cried out and clutched at her side.
"Here, let me." Filius gently helped Minerva to her feet and led her to the armchair nearest the fireplace. Once he'd eased her into it, he drew out his wand and dried her robes, re-ignited the fire to a roaring blaze, then conjured a hot toddy, which he urged her to sip while he draped a blanket across her lap. "May I?" he then asked, gesturing at her side.
"It's nothing, just a bruise," she said, but nonetheless shifted so he could pass his wand over the area, wincing slightly as the Healing Charm did its work.
"It's not nothing, you had a cracked rib," he said. He pulled up a nearby ottoman and climbed up on it. "Now tell me what happened. What's this about a dog?"
She set down the toddy, then smoothed the blanket over her knees, her hands still shaking slightly from whatever had upset her so. "It was dreadful," she said, shaking her head. "As you may be aware, the moon is full tonight, and I had gone out to keep watch over young Lupin, as I have done every month since he first came to Hogwarts."
"You're such a conscientious Head, Minerva," Filius said, trying to reassure her. "I don't know that any of the rest of us could have welcomed a werewolf into our respective Houses so readily."
Her lips thinned as she gave a brief smile of acknowledgement. "It was Albus' idea, initially. I can't claim credit. He feared the boy might have trouble making friends if he was indisposed on a regular basis."
Filius chuckled. "I'd say neither you nor Albus should have any further cause for concern on that part."
This time, her smile was warmer, fonder. "He's very fortunate to have Black and Potter in his corner."
"Don't forget the Pettigrew boy."
"I haven't." Her gaze grew distant and thoughtful. "Though I don't think Lupin would feel the loss of Pettigrew's friendship as keenly as he would that of the other two. The three of them are their own little pack."
"Perhaps you're right. You know the students in your own House far better than I do, and rightly so." He flicked his wand to replenish her toddy. "You were saying you'd gone out to make sure Lupin didn't come to any harm?"
"Mm," she said as she took a deep draught, then leaned her head back and closed her eyes. Filius could tell from the faint flush on her cheeks that the jigger of Firewhisky he'd added to soothe her nerves was beginning to take effect. When she opened her eyes, he could see that they'd grown bright. He made a mental note to omit the Firewhisky if she needed another refill; Minerva had never been able to hold her liquor.
"Minerva, what happened?" he asked. "Lupin didn't attack you, did he?"
She shook her head vehemently. "He's never been any sort of threat to me, not when I'm in my Animagus form. No, it was definitely a dog that attacked me."
"A dog?" Filius hopped off the ottoman to look out the window she'd entered through. A thin layer of frost covering the ground glittered in the moonlight, but there was no sign of any dog.
"A big black one. Probably about the size of a deerhound."
"Gracious. Any idea where it came from?"
"That's just it -- I've never seen it before, and I can't for the life of me understand how it was able to get on the grounds."
He came back around to resume his seat before her. "Tell me exactly what happened tonight."
She drained the rest of the toddy before speaking. "I had just finished my inspection of the greenhouses -- a great place for a mouser, I might add, if I were so inclined -- and was crossing the pumpkin patch to see what the giant squid was up to, when it came at me from out of nowhere." She shuddered at the memory. "It came from downwind of me, so I never caught its scent, and it might as well have been a ghost for all the sound it made."
Filius clucked his tongue in sympathy. "What a horrible experience for you."
"The odd thing is..." She sat up suddenly, her spine straight and unyielding. "The odd thing is, it didn't actually attack me. It chased me." She grimaced. "Up the Whomping Willow. That's how I came to be in this state. That wretched beast chased me up that damn tree, barking as though it were having a wee bit of sport, and wouldn't let me come down." She slumped back.
"I gather the tree wasn't pleased."
"Not at all." She reached across her torso to press her hand against her side. "Thank Merlin cats are nimble, else the damage could have been much worse."
"How long were you trapped?"
"I'm not certain... an hour, maybe? What time is it now?"
"Almost two, then. The brute eventually stopped barking at me, but it wasn't about to let me down. If I could have safely changed back into human form... well, I would have taught that nasty beast a lesson or two." She reached up to flutter the tips of her fingers against her brow. "I don't know what I would have done if I hadn't seen the light in your window and managed to reach the ledge. I might have ended up spending the whole night out there, waiting for Hagrid to chase it off."
Filius laughed. "Knowing Hagrid, he would have taken it home and fed it."
Minerva shook her head. "You're probably right." Just then she yawned widely. "Forgive me!" she exclaimed, her face red. "I think that Firewhisky you slipped into my drink is taking effect."
"I had hoped you wouldn't notice," he said brightly, smiling when she yawned again. "You've had quite an adventure tonight." He suppressed a yawn of his own.
"Filius," she said, leaning forward, "would it be too much of an imposition if I were to curl up before your fire for a little while? After what that dreadful dog put me through, I need a little more time to put myself back to rights."
He understood what she needed and climbed down from his ottoman. "Of course, Minerva. You're more than welcome to spend as much time as you need. Do you want a cushion to rest on?"
"No," she said, rising stiffly. "The hearth rug will do, and the warmth of the fire will take care of the rest." She reached out her hand to him. "Thank you... for rescuing me, and the toddy, and, well... I... your friendship means so much to me."
He took her hand and bowed low over it. "As yours does to me. Knowing you has been one of the great joys of my life. Never hesitate to ask for my assistance in anything." He released her hand and stepped back to retire to his bedroom. "Stay as long as you like. In the morning, we'll both go see Albus about this strange dog. For all we know, it could be a threat to our students as well."
"I agree." Then her tall, willowy form folded in on itself, leaving behind a tabby cat with spectacle-like markings around its eyes. She meowed once at Filius, then trotted over to the hearth rug, where she curled up, one front paw extended forward, and began to purr.
"Good night, Minerva," Filius said, smiling tenderly. He then turned and entered his bedroom, closing the door behind him.