Oh god colds are hell. Help. I can't even taste my curry- this is torture.

Also, England v Italy on Saturday in the FIFA World Cup. In the immortal words of Warren Ellis: "If you don't follow soccer, pretend I just said 'Sick Pandas vs Hail Of Buzzsaws'." He's not wrong.

If you see errors or Americanisms, let me know. :)

Her heart rate won't drop, she's covered in soot, and she stinks of smoke and sulphur, but Mary Morstan has never felt better. Not happy—that's not quite the word for it—but good. That's possibly a bit not good of her, given that the church is still sort of on fire and everyone is sitting on the kerb as the paramedics, police, and fire crews swarm about, but whatever. She's entitled to it. Olivia, Ciara, and Valerie are alive and safe.

Small, strong hands land on her shoulders as John lowers himself to the ground behind her. He tucks himself around her lovingly, nuzzles behind her ear, and sucks in deep, calming breaths. She closes her eyes and leans into the scenting.

"You corking great wonder," John rumbles into her neck. Mary doesn't bother suppressing her delighted shudder. "Don't ever scare me like that again."

A long arm curls itself around Mary's front as Sherlock sits down next to them and leans. "He means to say, 'Don't ever do that again, not without us there to watch you do it,' of course," the detective remarks. "For a teacher, you've a stunning predilection for recklessness."

Mary tips her head back so it rests on both John and Sherlock's shoulders. "I'm a teacher," she agrees, "and she's my student. I'll do anything to protect her."

John's lips curve into a smile as they rest over the skin just beneath her jaw; Sherlock's embrace tightens. "I know."

For a moment, they simply sit there all wrapped up in one another, completely ignoring the soot and the residual stink of smoke in favour of appreciating the fact that they're all alive and intact.

It's a lovely moment, but it isn't long before Mary can almost hear the gears in Sherlock's brain whirring. "Sherlock."

"Hmm?" He's just a bit too relaxed—definitely thinking.

"If you have questions, ask them."

John huffs out a silent chuckle into her neck as Sherlock's fingers immediately begin the impatient, thoughtful fiddling he'd been trying and slowly failing to restrain. "I was given to understand that phoenixes burst into flame upon death."

"Yep," Mary answers gamely, popping the 'p'. "They burn up when it's natural, unnatural, or self-triggered. At its peak, it's easily hot enough to melt tungsten."

That gives Sherlock pause, if the lull in his fidgeting is any indicator, but he's back to it quickly enough. "The head was still there," he says. "Is that typical?"

Mary shakes her head. "No, no it isn't. I wish I could say I had it in mind the entire time, but it was really a result of an unexpected interaction between the ward and charms I'd scribed." Tugging her bag around, she shows them the silver paint pen she'd used to write and tugs at Sherlock's hand. "Rule one: always know where your paint pen is. Rule two: always know where your backup paint pen is. Towels are helpful; pens, doubly so." Sherlock unfurls his fingers and flattens his palm at her behest. "It's possible to interlock wards with other written magic to create conditional triggers, filters, that sort of thing. All I knew at the time was that it was a demon—"

"Those exist?" Sherlock demands.

Mary nods. John and Sherlock look at each other, startled and worried (John more so than Sherlock on the latter). "They do. The phoenix had... well, she was psychopathic, put simply, and decided to find a 'friend', but that's not the point. I knew I was dealing with a demon, one that liked fire magic, so I wrote a fire ward." She sets the pen to Sherlock's palm and draws a complex set of runes. "Problem is, I only know the absorptive sort—they're energy-expensive and don't work too well if you're surrounded by fire and have nowhere to dump the heat they sponge up.

"Now, the ward as written absorbs and stores heat energy from inside the circle. I thought of you, Sherlock, and that made me think of science—yes, yes, I know, shut up—which made me think of conductors, which made me think of circuits, so I wrote a channeling charm that would take the stored heat energy from the ward's reservoir and dump it into powering the ward." She draws the rest of the unit sigil of the warding circle.

Sherlock treats both Mary and his palm to a very impressed look. "Clever," he says, pleasedly, "but how does that result in a beheaded phoenix?"

"There's the happy accident," Mary laughs. "Once the phoenix started burning off the human shape it had taken, I was worried—if it decided to self-immolate, I wasn't sure if the ward would hold up—but all that happened was the temperature in the circle started dropping like a rock."

The low, wickedly delighted laugh that escapes Sherlock sends shivers of delight down Mary's spine and does something very similar to John, if the way his breath shudders against her cheek is any indicator. "A feedback loop," he rumbles with quiet glee. "The phoenix made things hotter, which made more heat energy available for the ward to sink and power itself with. More power meant a more effective ward, which meant more heat energy being removed—temperature drop. Fourier's Law states that heat transfer is proportional to the negative energy gradient and to the area perpendicular to the gradient, so the more the temperature dropped in the cylinder demarcated by circle, the faster heat energy leaked into the cylinder, which—"

"Yes, yes, yes, we get it, Professor Holmes, feedback loop," John interrupts with a laugh. He wraps his arms tight around Mary and nuzzles her with a happy rumble. "Fucking magnificent genius, you."

Mary leans back into his ministrations. "Jammy, mostly." She cups Sherlock's open hand. "I had no idea if it would work. If anyone's tried partially immolating a phoenix before, they've been burnt to a crisp right along with it. I had no idea, yet I decided to taunt the demonically possessed flaming bird of fire into the containment circle so I could bash its head in on the floor and hope my little circle stopped it burning? You ought to have me sectioned."

A shriek is the only warning any of them have before a small, soot-and-cinnamon blur impacts Mary's side. Completely heedless of John's limbs or Sherlock's arms, Olivia Cartwright wriggles her way into Mary's lap and throws her arms around her teacher in as ferocious a hug as her little frame can manage. "Miss Morstan!" she cries, leaning back and bouncing up and down. "Miss Morstan, you killed Bad Fawkes!"

John ducks his head into Mary's back and giggles; Sherlock looks baffled. Mary can only laugh. "I'm sorry you had to see that, Olivia—"

"IT WAS THE COOLEST," Olivia exclaims, pumping her fists for emphasis, "Bad Fawkes was all 'LITTLE BIRDIES' and you were all 'Go away!' and then Bad Fawkes was a giant scary shouty bird with fire not a lady and you were all 'Come and get me!' and—" here, Olivia does something very twisty and complicated with hands and arms as she accompanies the motion with gratuitous use of the sort of sound effects only small children can produce, "—and then Bad Fawkes was on fire except for his head and that was BETTER THAN HARRY POTTER." Apparently winded by her outburst, Olivia flings herself into Mary's arms again and pants.

A snort escapes Sherlock as John just keeps giggling into Mary's back. Mary just rolls her eyes at her boys and returns Olivia's hug. "I'm glad you're so excited about it, Olivia. You're very brave, you know. I was scared!"

Olivia leans back again with her Serious Business face on; dark brown eyes meet Mary's green ones. "Neville Longbottle was scared a lot too but he killed the Bad Snake in the Deafly Hello movie Ciara showed me, so it's okay. I knew you would help us. You're a teacher. That's what you do." She nods sagely, as if this is some unassailable truth that she's imparting into Mary's keeping.

"It's true," John says as he settles himself next to Mary on the kerb. "Why, just last week, she solved the puzzle that Sherlock and I had been stuck on for days. We caught four bad guys because she helped."

The smile that Olivia favours John with is as smug as it is proud. "That's because Miss Morstan knows everything. She's probably the smartest person ever." Because she's facing John, she misses Mary's teasingly raised eyebrow and Sherlock's tolerant eye-roll. "She helps me with reading. I can read a whole Cam Jansen on my own. Oh. Hi, Mummy!"

Valerie Cartwright, soot-smudged and wrapped in an orange blanket from one of the paramedics, stoops to hoist her younger daughter into her arms. "There you are."

After passing Olivia to her mother, Mary gets to her feet and tries to straighten out her clothing a little bit. "Valerie, I'm so sorry you had to—"

Slowly, Valerie shakes her head and raises one hand. "Mary. I d-don't..." She bites her lip, takes a deep breath, closes her eyes for a bit. "I don't... know what that thing was. I'm not sure what you d-did, or how, or... or what you are, either, but... thank you." She gives Mary a small, haunted, but genuine smile, her raised hand coming to rest on Ciara's shoulders as her elder daughter shuffles up. "Thank you, Mary."

Olivia waves happily over her mother's back as Valerie turns and guides her girls back toward the ambulance and the paramedics; Mary waves back, completely unable to stop smiling.

It isn't until they're in the back of a cab several hours later when Sherlock finally thinks to ask. "Mary."

Mary starts and looks up at him blearily from John's shoulder. "What?"

"How did you banish the demon? Wouldn't it... linger?"

Mary closes her eyes again and smiles. "Oh, it did, but not for long." The laugh that escapes her is almost wicked. "You see, Sherlock, the first classroom I observed as an undergraduate was in a little Christian school run by an American." She shakes her head and buries her face in John's shoulder. "They have a telly programme over there, one with talking vegetables."

"Mary," John breathes, awed and almost remonstrative. "You didn't."

Sherlock looks between the two of them, confused. "What? She didn't what?"

It's very, very fortunate that the cab is already pulling up to Baker Street; the vehicle hasn't even come to a full halt before a thoroughly horrified Sherlock Holmes is scrambling out of it, chased by the sound of VeggieTales in Mary's soft, slightly drowsy alto.

What a ride.

Thank you so much for sticking with me through this! Do expect more; there's so much I've yet to explore in this universe. As before, if you've a particular supernatural or mythological creature, deity, or entity that you would love to see played with, please feel completely welcome to suggest it to me (as well as sources I might use to get things as right as I can make them)! Unto Dust and several of the last chapters in Perfect Nonsense have been the result of requests. :)

Again, THANK YOU SO MUCH for your comments, favourites, follows, and read-throughs- it's been a real joy to write, and I hope it's been a joy to read. :)