He almost collided with a man exiting a corner shop as he turned right off the High Street and up the hill.
Whilst they never actually made contact, it was enough to send the man's shopping up in the air and all over the pavement.
Darwin didn't dare stop, driven by an urge that whilst not totally forgotten, had remained subdued enough for the feeling to seem new.
He heard the man shout expletives after him, and then a breathless Cassidy apologising on his behalf as she ran past the scene some seconds later.
The road up the hill was lined with Edwardian semi-detached houses, but to Darwin's dismay, at the top it bent to the left instead of right toward the source of the smell.
He was contemplating jumping over a few gardens when he saw a narrow passageway leading down the other side of the hill.
He took it, running blindly into darkness.
He couldn't hear Cassidy behind him anymore, but if they did lose each other, she knew where the squat was and could make her own way back.
She might seem like easy prey to some of London's nightlife, but he wasn't the only one with a hidden side.
Besides she was pretty streetwise and knew how to take care of herself.
By the time he reached the bottom of the hill, emerging out of the darkened passageway into a cul-de-sac, it was snowing hard enough to coat the world like icing sugar.
That would soon turn into a covering several inches thick and possibly worse if the weather reports were to be believed.
The snow also seemed to be playing havoc with his sense of smell, as upon reaching the bottom of the hill, he lost all trace of the scent.
London was too labyrinthine to risk continuing to run, so he stopped and paced around, waiting for the whiff of blood to return.
His senses were on overdrive this evening. He could smell Cassidy long before he heard the heavy flat fall of her boots pounding tarmac.
She came tearing down the passageway, bursting out into the road.
"I... thought... I'd... lost... you..." she panted, hands on her knees, bent forward trying to regain her breath.
He never answered, instead continuing to sniff the air, pacing in every direction.
The presence of Cassidy made things more difficult, her scent overwhelming in his heightened state.
Perhaps she was drowning out the smell, perhaps he could ask her to leave.
It couldn't have just disappeared, could it?
Darwin asked himself.
If the body was being loaded into a van to be dumped in the Thames or somewhere it might.
Shit, if that was the case it was nothing more than a fucking cock tease.
There would be no way he'd be going back to rats, not tonight.
He'd grab someone coming out of a club or jump someone walking home on their own.
Fuck Cassidy and her principles.
He was just thinking on how he'd justify this to her, when a gust of wind brought the scent again, much stronger this time.
He was close, and better yet, the body was still warm.
He sniffed once again to be sure of the direction and started running down another alleyway toward the source, his feet now leaving footprints in the snow.
"Oh great," said Cassidy as she chased after him, "more running!"
The alleyway was leading to a rougher part of town, which pleased Darwin.
People would be too busy locking their doors to worry about looking out of their windows.
Cassidy kept up this time, only a pace or two behind him.
His Blood Lust led him round the back of a parade of shops, lined by the buildings on one side, and a row of dilapidated garages on the other side.
Overflowing industrial wheelie bins littered the area, and they had to make their way through.
It was dark, the streetlights along the road they had just come from, blocked by the shops.
The only illumination was the odd security light fixed to the back doors of the shop premises, casting pools of light in the pitch blackness.
Darwin sensed something was wrong.
He stopped and hissed with dramatics that would have made some of the older members of the Vampire Council proud.
There, slumped against a garage door and lit by a tiny pool of light that cast heavy shadows, was an elderly man, eyes unmoving and staring through Darwin just like the London commuters had.
His bald head, chubby build and white beard would have made him an excellent department store Father Christmas, but in place of a red and white outfit he wore a green three piece suit, the side of it stained from the blood that was running down from the back of his head.
Across the dead man was what looked like a black branch.
It seemed to emanate from behind the wheelie bins and then curl to a point on top of his chest.
It was only when Darwin hissed for a second time that he saw the suckers on the underside, and watched in amazement as it twisted and recoiled back behind the bin.
"Tentacle," said Cassidy.
"Please tell me you saw that tentacle."
Darwin ignored her, the smell of blood now intoxicating to the point of overpowering him.
He could think of nothing else.
He grabbed the head and tilted it sideways.
He sank his teeth deep into the neck, like a starving man on a leg of chicken, and drank.
He'd tasted human blood many times before.
He knew what to expect, knew how the taste changed when someone was a smoker or a drug user, but this blood tasted different, it tasted...
Darwin withdrew and spat over the body.
The two puncture wounds in the neck continued to ooze out blood, staining the snow red as it pooled around the body.
Darwin coughed and for a moment thought he was going to be sick as he retched once or twice.
"It's sour!" he exclaimed.
"Sour?" questioned Cassidy still looking in the direction the tentacle had retreated.
"Can blood even go sour?"
Darwin felt rage surge through his body, probably a release of the adrenaline that had been fuelling his Blood Lust.
He twisted the corpse's head, pointed the bloody neck toward Cassidy and snapped, "You wanna try?"
Unusually for Cassidy, she kept quiet, as Darwin stood up and paced around the body, hands in his hair.
"Fuck!" he screamed, kicking at bins, pounding on garage doors and generally lashing out at anything in the near vicinity.
"Fuck!
Fuck!
Fuck!"
After so long without proper food, to have this happen, was beyond cruel.
He fell to a crouch, put his head in his hands, and wept.
"Darwin, it's OK," said Cassidy, more chirpily than he would have liked.
"We'll find another body. Maybe we'll get you some rats on the way back?"
Darwin noted she kept her distance.
Was he really that much of a monster when in Blood Lust that she felt the need?
He'd never been violent toward her, never threatened her, yet still she remained a couple of steps away.
"Don't you understand?" he said as his urges subsided and his fragility seeped back into him, "I can't control this."
He felt weak for saying it, but it was true. However much Cassidy went on about him being half human he was also half vampire.
Why couldn't she accept that?
He wished he could be the man she wanted him to be, but this wasn't a case of being good or evil, it was about survival.
He looked at her, trying to choose the right words to say; words that would make her understand what he was going through.
Yet looking at her faint reconciliatory smile, he knew those words, that reason, didn't exist.
He wiped his eyes with the back of his hand, stood up and offered her the faintest of smiles.
She came running up, threw her hands around his abdomen and rested her head on his shoulder.
"It'll be all right, Darwin," she said squeezing him tight.
"Trust me, it'll all be all right."
He looked down at her and took solace from her never ending faith: a faith in him and the world around him that he was blind to.
Just as she'd never understand his vampirism, he'd never understand her belief.
They were close enough to know what the other was feeling, yet they were still so alien to each other.
He bent back down to the body and started rummaging in all the pockets for anything that might be of value.
The wallet had just over a hundred pounds in it, a fact that made Darwin feel that this whole episode hadn't been entirely wasted.
The corpse's waistcoat pocket held a small hardback notebook, which Darwin handed to Cassidy.
"Could be worth something," he said as she took it.
“E. F. McFadden,” she said reading the name embossed on the front.
“Who do you reckon he was?”
Darwin shrugged.
“Who cares?”
He pocketed the majority of the money as Cassidy stuffed the notebook into her coat.
In the distance a siren wailed.
It was unlikely to be destined for here, yet it was enough to make Darwin pat the corpse's pockets over one last time and then stand.
"Come on," he said flashing one of the corpse's tenners at her.
"At least Mr McFadden here can give one of us a hot meal tonight."
CHAPTER TWO - A Knock At The Door
Maureen Summerglass sat in front of the fire in her favourite armchair covered in quilts and blankets.
Despite the heat from the flames that were causing her to sweat she still felt frozen, a hint of a draft managing to get under the layers of bedding and chill her toes.
Winter wasn't so much something that was endured as fought.
Most winters she got off lightly, the fire or the aged electric heater enough to keep her lounge warm.
But on nights such as tonight she felt like King Canute trying to stem the tide.
She had no central heating or double glazing in her little semi-detached cottage - she dare not - so she'd barricade herself in by the fire and hope that the winter would not last too long.
The water taps were all turned on to help prevent her pipes from freezing, because she couldn't have any repair man come in and fix them if they broke.
Not with what was downstairs in the cellar.
She dare not let anyone accidentally find that.
It was especially cold tonight, such that her cats, Nicholas and Neil, wanted to climb under the blankets with her rather than just curl up on her lap.
Whilst she preferred the comfort of her own bed, she was wondering whether it would be better to stay here for the night; if she was cold here, what would her bedroom be like?
She had been expecting the knock at the front door, yet when it finally came it still made her jump.
She didn't want to get up.
The hallway would be frozen.
She was sure that by the time she returned what little warmth she currently had in her body would have left her.
But if she was cold sat here in front of the fire, heaven knew what Ernest was feeling out there on the doorstep.
Still, she thought as she got up and wrapped one quilt round her like a shawl, the man was still over four hours late.
She opened the door between the lounge and draughty hall, the difference in temperature hitting her with a shiver.
Whatever that man's excuse, he was about to be given a talking to.
She unlatched and unbolted the heavy wooden front door and began to open it.
"So Ernest, you gonna tell me where you've been all..."
But it wasn't Ernest, it was her next door neighbour, Sally.
Maureen managed to stop herself from flinging the door wide open, and luckily too, as Sally was already moving to make her way into the house.
She was covered in snow.
Beyond her, the front garden, path and even the road that ran along the front were covered in a thick blanket of winter.
An icy blast that blew snow swirling into the hall gave Maureen the perfect excuse to close the door to just a crack.
"Oh Sally, it's you?" said Maureen trying to feign pleasant surprise through the eye-width gap.
"Of course it's me," mumbled Sally indignantly, almost unrecognisable with her coat zipped up to her nose and hood pulled forward to cover her eyes.
"You don't think anyone else would be crazy enough to brave this weather do you?"
Maureen eyed the path pockmarked with Sally's footprints and then the snow at Sally's feet that reached to just below her knee.
"Oh, it has been snowing, hasn't it?"
"Snowing? They've had three foot of the stuff in Elstead.
And it's so thick up on the Hog's Back, they've closed the road.
Simon can't even get home.
Luckily his firm is putting him up in a hotel in the city.
I don't know what he would have done otherwise."
Maureen wasn't quite sure how to respond, but Sally never gave her any time.
"Well, Simon said I had to check in on you.
Old people and being vulnerable and all that."
"That's very kind of you," Maureen replied, trying to subdue sarcasm.
"It's the least we could do.
Now we've finally finished doing up the spare room, if you want to pack some clothes you can stay with us until the snow melts.
Mind you, we've still got all the tools in there, but you can put up with some power tools and a workbench, can't you?
Just for a couple of days."