An: who who who who who (these aren't becoming song fics honestly I'm just running out of ideas for chapter titles)

26th December 1887

Jenny was sat in the kitchen eating breakfast, debating how precisely to tell Vastra she would leave when Vastra herself swept into the kitchen, brandishing a letter at her.

"We have a case. If you wish to assist me." She said stiffly.

Jenny blinked at the sudden acknowledgement of her presence but nodded, curiosity overcoming surprise.

"There have been a series of attacks." Vastra explained. "Violent but not fatal. Indeed, most report that they weren't even wounded." She glanced at the letter again.

"So why 'and it to us? Though people gettin' attacked an' not bein' 'urt is strange I'll give yer." Jenny responded in kind. If Vastra was going to act as if nothing had happened, she'd go along.

"The attacker is reported as a large and terrifying dog that vanishes upon closer inspection. There has been no luck tracking it down."

Jenny frowned. "Boggin said 'e was attacked by a dog. We all laughed, thought he'd bin fillin' up ter the knocker."

"It may be that there have been more attacks that have not been reported." Vastra shrugged. "But if your urchin has already seen it, he may be a good place to start investigating."

"I'll go see what I c'n find out then." Jenny got up, fetched her cloak and walked out. The exchange had been business-like but at least Vastra was talking to her again.

She checked at Parker's house to see whether Boggin was staying there but didn't see him and ended up outside Jess's flat instead.

"Blimey. Two visits at Christmas? I feel special." Jess raised her eyebrows when she opened the door to find Jenny standing there. "What's the occasion?"

"A case." Jenny shrugged.

"Ah. I ain't 'eard or seen nuffin' an' I deny everythin' an' everyone wot claims I did." Jess saw Jenny's expression. "But I s'pose I c'ld walk about with yer fer a bit if yer in need of some company."

They walked about London in silence, Jess waiting for Jenny to talk and being disappointed.

"Trouble with 'er indoors?" she gave in and asked eventually.

"Wot?"

"Face like wet washin'. Take it she weren't pleased about yer stayin' out all night after all."

"It weren't that."

"Oh?"

Jenny ended up telling Jess the whole story as they wandered, feeling relieved even if Jess's expression was less than impressed.

Jess shook her head. "You ain't arf a berk. Tell 'er will yer? Either she loves yer an' thas fine or she don't an' yer move on."

"You don't understand. She's a Silurian."

"Well unless they don't 'ave such a thing as love in Silurian Land, don't make no diff'rence does it?"

"I don' think she…"

"Oh shuttit wiv the excuses. I let yer jaw me ear orf din't I? I've gi'en yer my advice now put a sock in it."

Jenny's feet had guided her back to the Docks as they'd walked and she leaned against the railing once more, feeling slightly put out. It might seem simple enough but living with Vastra was anything but. Easy to say.

"So this is where time went wobbly fer yer ey?" Jess looked around her, feeling that she'd been slightly harsh on Jenny.

"Don't turn round too many times is all I'm sayin'." Jenny snorted.

"Why not ladies?"

They turned round, ignoring Jenny's warning, to find a tall black man leaning idly against a railing. He spun around twice, his long red coat and his dreadlocks whirling as he did so.

"See? Nothing untoward."

"'oo are you?" Jess asked, intrigued. "Is this the normal kind of person you run into on yer cases?" she stage-whispered to Jenny. "Might 'ave ter come out with yer again."

"I am the Marquis de Carabas." He walked towards them, steepling his fingers and grinning. "And I come here as a messenger from a certain rat speaker, who now owes me a favour, to warn you that you might be in a bit of trouble. She's doing the best she can to get you out of it but it might not be enough." His expression was one of mock sorrow.

"Trouble?" Jenny sighed.

"Well we c'n 'andle ourselves can't we Jenny?" Jess returned his grin.

"Against that?" he pointed behind him, turned once more and disappeared.

Jess's eyes went wide. "Bleedin' 'ell."

Jenny's eyes went wider and grabbed her sister's arm. "No, thas bleedin' 'ell!" she pointed to a huge snarling hound that had appeared at the end of the street. The case had tracked down Jenny this time, rather than the other way round. "RUN!" she pulled her sister down the steps, dodging from a boat to another street.

They pelted back to Paternoster Row at full tilt, not even sparing breath to curse further.

Slamming the back door behind them, they rested against it, gasping in air.

"What in the name o' saints was that?!" Jess asked when she'd recovered slightly.

"I got no idea." Jenny shook her head.

"Is this wot yer life is like? Yor cases that yer do?"

"Mostly. Sometimes it's worse."

"Worse?" Jess looked at her in alarm and disbelief.

"Well there were these things called Cybermen y'see an'…"

There was a thump against the door and they sprang away from it to see claws raking down it.

"Bugger that!" Jess squeaked.

"The swords!" Jenny grabbed her arm once more and they fled to the basement, Jess nearly falling down them in her haste.

Jenny grabbed the first sword of the rack, fumbling to get it out of its sheath. Jess looked at her in only mild surprise this time. She was learning a lot about her sister.

"Wot kind of person 'as swords in their basement?!"

"People who go on adventures wot need swords." Jenny pushed Jess behind her as the hound appeared in the doorway.

Now that it had them cornered it stalked very slowly down the steps towards them.

Jess let out a whimper. "Jenny…"

"S'alright." She gulped, wielding the sword before her and praying to whatever deities she could think of.

It pounced from the bottom step and she dropped to the floor, rolling underneath it to strike with the sword at its underbelly. It yelped and sprang away from her. She scrambled to her feet as it circled her, snapping at her. Another leap which she dodged and drove the sword into its side. A yowl of pain this time as it pulled away, taking the sword with it.

"Jenny!" Jess called out in fear, seeing her sister suddenly defenceless.

Jenny ignored her sister and watched the dog as it turned its head, trying to bite at the sword. While it was occupied she grabbed the other sword of the set, flinging the sheath to the side.

It lashed out at her with giant paws, trying to knock the blade from her hands, leaving deep gashes along her arms and she cried out in pain before striking back, forcing it to retreat.

"Jenny?!" The sound of Vastra's voice did distract her and the hound charged at her.

"Jenny!" Jess yelled again in warning.

Jenny looked back toward the hound and brought the sword up on instinct, falling back into one of the stances Vastra had taught her. Blood splattered her as the sword drove through the hound's eye, helped by the hound's own momentum. The body fell on top of her and she struggled frantically in an attempt to get out from underneath it. Jess darted out and tried to drag the hound off her but Vastra stopped her and with a heave pulled the body away before kneeling down to help Jenny up.

Jess was distracted from staring in awe at Vastra by a shimmer in the air above the body. Her brain saved itself from being overwhelmed by utterly failing to be impressed by the small figure in blue robes that appeared from the shimmer, despite the small blue flames licking up and down its arms. It bowed its head over the dog and then turned and looked at the three of them.

"You have killed my Hound, Jenny Flint." Its voice was sorrowful.

"It was gonna kill me, wotcher expect me ter do!" Jenny snapped, adrenalin making her uncaring of shimmering blue people appearing out of thin air to judge her. She got to her feet, wincing at the sharp pain in her side. The hound had been heavy. "Wot you got against me ter go round settin' that on me anyway?"

Jess blinked at Jenny casually answering it back with ease, as if she regularly met small balls of flame that set dogs on people.

"You trespassed on the Isle of Dogs, you walked the One Path through the swamp and yet you did not pay the toll."

"You mean the underworld?"

"What a crude term. It is part of Below, not some hellish landscape." The figure sniffed, a little fussily. It sounded like a fire popping on a wet piece of wood.

"Woss a Below?"

"A Below. A beneath. Under you. I am the Guardian of that territory, born of the swamp it was long ago. It is my responsibility to ensure its upkeep and you," it pointed a flame of a finger at Jenny. "an Upworlder of all things… Of course, some silly little rat speaker came to me with a most compelling tale, claiming it was all her fault you stumbled onto the One Path, that you couldn't possibly have known…" its eyes narrowed from round marbles to slits of flame. Jenny could feel the increase of heat from the glare. "You must be something special for her to risk that much. I am not an approachable person." It grinned most unreassuringly, dripping small blue-ish green flames from its mouth that landed on the thankfully stone floor.

Jenny stayed silent, mentally re-assessing the strange figure. It wasn't as large or terrifying as its hound but fire was a fire and the flames had rolled.

"She is." Vastra surprised Jenny by speaking up and walking to stand in front of her.

"You vouch for her too?" The Guardian looked up at her, considering her for a moment. "I remember your race, little lizard. Your great cities were under the ground but even then they had a Below."

Vastra suppressed a shudder at this unwelcome knowledge. She'd been entirely unaware of any "Below"s and if they were full of flickering fiery figures in blue robes that went round trying to kill people with dogs she was rather glad of that fact.

The Guardian was still staring at Vastra. It huffed a small cloud of steam and then flared until it was Vastra's height.

Jenny heard a small whimper from the direction of Jess and pushed past Vastra to confront the Guardian.

"So you come 'ere wantin' a toll is that it? Well we got money. We c'n pay fine enough." She glared up at it.

"I do not require money." It crackled, its thin mouth twisted into a smile at the idea. "We do not use it Below. It is a barter system. One of exchange. Equal exchange. For a certain degree of equal. The toll would not have been much; some small useful item about your person, something irrelevant to you perhaps but Below, of vital significance. But you did not pay it. And ignorance is never an excuse. Now you must pay a fine enough." It spat her words back at her.

"Or what?!"

"Or your soul will walk the One Path forever. And no amount of spinning widdershins will get you out."

"Wot'd'yer want then?" Jenny's jaw clenched as she tried to contain a rapidly growing fear.

"What I sent my hound out to retrieve. It was a Flint that trespassed into my world. Thus I decreed a Flint would be the payment."

"No!"

It held up a hand to stop Vastra's protest. "That is the price. Get in my way, Silurian, and I will cook you inside your scales and feed you to the rest of the dogs on the Isle." Its eyes had flecks of soot burning in them now. It held out a hand to Jenny who stuffed hers in her pocket. "There are worse things than death." It added, noting the gesture.

"Awright then." Jess piped up from her corner. "Take me. I'mma Flint too y'know." She walked in very small steps across the basement.

"She goes by the name o' Blackett these days." Jenny said hurriedly. "Don't count." She gave in and reached out a clenched fist towards the Guardian's.

"Oi! I'm still a Flint…" Jess protested.

"Jenny!" Vastra's voice broke but Jenny's gaze did not falter as she opened her hand and dropped her flint onto its palm.

"Gribble give me that." Jenny explained quietly in the stunned silence that followed. "I kept it all these years, as the on'y thing I really 'ad to call mine."

The Guardian stared at the small stone in its palm. "A flint."

"You said yer fine was a flint, well there one is." Jenny trembled as its gaze turned on her.

"A trick of words!" It snarled. "But my own words I concede. Very clever, Jenny Flint. Very clever." It hissed, shrinking down to its original size. "I take your flint. You should find the Gribble you spoke of and thank them. Their gift has just saved your life."

"'e died." Jenny's voice was quiet still, but it carried.

The Guardian looked up at her. "I see. Not just a flint then. Much like yourself." It bowed to her. "Venture into my realm again without paying a suitable toll and I will set the rest of my dogs on you. Would you be able to fight them all I wonder?" It grinned, made a sound like a log splitting in two in a fire and disappeared.

Jenny stared at the spot where it'd been, her hand closing into an empty fist.

"Woo!" Jess whooped, clapping fiercely. "Blimey! You sure pulled a fast'n on ol' blue fire balls." Relief made her swear inventively as she hugged Jenny. "Thought you was a goner. Thought I was a goner. Bleedin' 'ell!" She let Jenny go, expecting to see her sister grinning with relief, puzzled at the sight of tears.

Vastra hadn't drawn a breath during the whole exchange with the Guardian and she let out a very long breath before walking over to Jenny, aware as Jess was not just how much the flint meant to Jenny.

"I'm sorry." She said gently, uncertain whether to offer comfort.

"I've lost me flint." Jenny sobbed as, with no such uncertainty, she flung her arms around Vastra.

Vastra gasped at the suddenness, a little winded but she needed no second invitation to hold Jenny tightly to her. "At least I did not lose mine." She whispered, keening softly as she buried her nose in Jenny's hair.

An: Arthur Conan Doyle got wind of this adventure and thusly the Hound of the Baskervilles was born. Well in this fic at any rate. But not for a while yet. I need to set up a suitable meeting for them…