My entry for the Castle Halloween Bash of 2016. Partially inspired by the 2015 videogame Until Dawn by Supermassive Games, starring Hayden Panettiere, Brett Dalton, Rami Malek and more (really, they did the voice acting and the motion capture, check it out, it's crazy!). It's an 80s slasher style videogame, sort of a choose-your-own-adventure type of game revolving around the Butterfly Effect theory of every single choice having a distinct effect in our life. Perfect game to play at Halloween (my husband and I did it last year, spent Halloween playing it and it was amazing, until we both grew too tired and started missing all the QTEs and nearly all the characters died). I'll try to keep it short and have it done by Halloween.

Unbetaed, all mistakes are mine and mine alone. I'm trying to give Alex, my awesome beta reader, more time to catch up with Sins Of The Father and Shadows (yes, Shadows is back on track, almost) as I wrote more chapters than she could actually go through. Set around Halloween in Season 5, right after Probable Cause.

All rights belong to Andrew Marlowe, ABC Studios, Supermassive Games and SONY.

"Come on Castle, the boys are already there!"

Rick hobbled down the unpaved road in a secluded part of North Central Park, skipping the pools of muddy, stagnant water that remained from the storm that had raged during the night. It was a crisp, late October morning and they were heading to the latest crime scene, and of course he had decided to wear some expensive leather shoes, totally useless in those conditions.

"You could have told me the scene was in the middle of Central Park!" he cried, trying to keep the soil off himself.

Beckett stopped and looked at him, with a loud sigh of resignation. "Castle, it's nearly November and last night it poured. Half of New York is covered in either mud or watered down trash. You should have realized yourself those shoes weren't the right ones to wear. I have boots myself!"

He groaned and finally reached her. "Good point. I guess getting interrupted in the middle of some hot early morning make out sessions dulls my observation abilities. I'll pay better attention next time."

"You say that every single time. Come on now, it should be close enough now."

A few steps ahead a uniform waved at them so they could move in the right direction. He showed them a secluded path in the trees at the side of the road that led to a clearing. The whole area was closed off with bright yellow police tape and surveilled by more officers wrapped up in their heavy winter uniforms. Autumn that year had decided to be colder than the usual and Beckett found herself wrapping her hands together to ward off the chill of the early morning as Ryan gestured them to come closer.

A woman in her early twenties or late teens lay on the wet grass on her side, her knees pulled up to her chest and her arms circling her knees as if to protect herself. She was covered in cuts and the parts of her face not covered by her hands were marred by dark welts, as if she had been beaten before she had tried to escape through the park. Her blonde hair was matted and full of twigs and fallen leaves, while her clothes were covered in mud and dirt.

"What do we have here?" she asked, kneeling beside Lanie, as the medical examiner took notes about the body in front of her.

"Meet Samantha Moore, age 20, resident in Seattle, Washington. Was found this morning by a dog walker when the good doggie shoot down the road and started barking. He reported to 911 around six thirty, first response came roughly five minutes later," said Ryan. "There's a hotel keycard in her wallet and all her personal belongings are still on the body. Cash, credit cards, documents, everything is here."

"Doesn't look like a mugging then. Signs on the body?"

"Except for the dirt and the visible bruises, she doesn't look like she was harmed. There are no gunshot or stab wounds visible anywhere, no bloodstains or anything that would point to a violent death, but I will know more after I examine the body. She has a bump behind her head, probably caused by blunt force trauma, but except for that, she looks in pristine condition, given the circumstances," explained Lanie.

"If you had to take a wild guess, would you say the bump is the cause of death?" asked Castle from behind them. Beckett turned to take a look at him as he stood a few steps away from them, his hands planted in his pockets, seemingly lost in deep thoughts.

Lanie shrugged. "Could be. Could also be internal bleeding from wounds covered by her clothes, I don't know. It doesn't really look like she died of natural causes or of suicide, at the moment."

He gave them a stiff nod, but said nothing else.

"Castle, what's going on your mind?" asked Beckett, as she noticed there was something deeply wrong in him. He was never that silent on a crime scene, nor he looked so worried.

He sighed. "I don't know… the name rings a bell. Can I see the face?"

Lanie took a picture before moving the hands off the face.

They all gasped when they saw the expression of utter terror permanently stamped by death on the girl's face. She looked like she had seen Death incarnate, like she had been terrified when she had died, and the cold and rigor mortis had fixed her last moment of terror forever on her face. The bawling, empty eyes, the mouth slightly open in a grimace of fear and the copious, congealed blood that had been dripping from her mouth painted the perfect picture of horror.

"I've never seen anything like this before!" stated Lanie as she hurried to take another picture. "I know that extreme effort and adrenaline, along with the cold can set off rigor mortis right away but… this is incredible!"

"And terrifying," added Ryan, slightly uneasy.

Beckett swallowed a hard lump that had formed in her throat. The case that had started like a random murder of a tourist was taking a strange turn, she could almost feel it, the weirdness of that case already creeping up her back and making her feel awkward and unsettled.

"You really don't remember her?" asked Castle then.

Everyone around them turned to look at him with inquisitive stares and glares. "No," replied Beckett as she stood up. "Why?"

"About two years ago she was found wandering in the woods in Western Canada during a snowstorm, delirious with hypothermia and fear. She claimed a serial killer was hunting her down and had killed all her friends back at the cabin she had been staying. Sort of a slasher movie kind of thing, police wouldn't even investigate until she became hysterics and almost forced them to go and check the cabin. They found six corpses, murdered in the bloodiest ways you can imagine. They were staying at a famous horror movie director's mountain lodge, his son among the group. He was missing and was reported dead given the extreme weather conditions outside. They never found the body."

Esposito, who had been occupied with taking statements up until then, walked closer. "And you know that how?"

"You know, I get bored easily and I go look for weird facts and news from time to time. This one creeped the hell out of me, I have to admit it," he explained briefly.

"You're saying she survived a massacre only to die two years later in Central Park?" inquired Kate. "I doubt that can be a coincidence."

Castle nodded, warily, as Ryan and Esposito exchanged a worried look. "Should we look for the report of that case while we investigate on this front too?" asked Ryan.

Kate nodded. "It wouldn't hurt. It's too strange, the only survivor of a mass murder suddenly dies and looks like she's scared to death? Maybe Castle's been rubbing some of his crazy theories on me, but I don't think this is a coincidence. Castle and I are going to check at the hotel, see if someone else was with her or if she had visitors. Espo, Ryan, you two handle the canvassing and the statements, I'll call Gates and ask her if she can call police in Canada and get the report, that should speed things up. See you later at the precinct."

She snapped a picture of her driving licence and another of the hotel keycard to show, before hurrying back to the main path and to the car.

"This is weird," snapped Castle after they had climbed into the cruiser.

Beckett started the engine and nodded. "Yes. I don't know if it's you, incoming Halloween or the case itself, but when I saw her face… and then when you told us… she looked like she had seen a ghost or something!"

"Think she might have died of actual fear?" he inquired, his fingers tapping an erratic rhythm on his knee as he maneuvered the car in the thick Manhattan traffic.

"Is it even possible?" He nodded. "Let's wait until Lanie has something to tell us. I don't really want to jump to conclusions, we might even find out that it's just a bunch of coincidences. Let's see what we can find at the hotel. Oh and let me call Gates, to see if she can get things going with Canada."

XXX

The doormen, after Beckett had showed him the badge and explained the situation, seemed extremely willing to cooperate. He was an elderly man, probably approaching eighty years old, and he seemed genuinely upset by Samantha Moore's death. As he led them to her room, he kept shaking his head and muttering things to himself, about how the world was turning into a living hell, how a girl wasn't even allowed to take a walk in the park without being harassed or worse and things like that.

"She seemed like a nice girl, you know? Polite, quiet… she's been here for a couple of weeks, I assumed she was looking for a more stable place to live in, I don't know."

"Did anyone come to visit her?" asked Kate.

The man passed the passepartout in the electric keylock and the red led turned green as it opened. "No one. She received some mail while here, a couple of big envelopes I supposed were books and the like. She paid for a month in advance, so I didn't bother much, but she had no visitor," he explained, his voice faltering.

"Thank you Mr. Roberts, we appreciate your help. We'll take a look around now if you don't mind."

The man nodded. "No, not at all. Do whatever it takes to get the villain that killed her! Poor Sam, she was such a good girl…" he repeated.

Beckett nodded, understanding, and fished a card from her wallet. "Please call me if you rember something. Anything could be important."

He accepted the small card and inspected it through the thick glasses. "Will do, Detective Beckett. I'll ask my son if he noticed anything suspicious too, he took my place downstairs for a couple of hours last week, when I had to fix a couple of plumbing issues upstairs."

With that, he walked back down the hallway to the elevator, limping slightly. Castle looked at her. "What are the odds that our killer decided to pay a visit to Samantha right in those two hours Mr. Roberts wasn't present?"

"Little to none." They both wore nitrile gloves so they wouldn't leave fingerprints around and she opened the door.

Inside, the room looked pristine. The bed was made, the small desk beneath the window was spotless, only a neat pile of files and books stationed there, right in front of a worn chair. Beckett immediately checked the small wardrobe and found absolutely nothing outside the ordinary, then moved to the bed. The table had a small drawer and she pulled it open. Inside, she found a Bible, probably untouched, a small satchel containing a number of over-the-counter medicines like a travel-size bottle of Tylenol, antihistamine, Aspirin and half used tube of ointment made to treat allergic reactions.

"Looks like she was prone to allergy," she commented, putting down the satchel. She found second one, bigger this time and found it also contained drugs, but the strictly prescription ones. "And she was also being cured for depression."

That piqued his interest. "Really?"

She nodded. "Yes. Prozac, Adderal… she's got a small drugstore in here." She checked the label and then counted the pills in the containers. "She also looked like she took them religiously, these were all filled three weeks ago, it's a month supply and there are the correct number of pills in them. She looked like she was taking care of herself."

"She was also into First Nations history and mythology," he commented, lifting one of the books he was examining on the desk. "Native American Myths And Legends by John Malick." He flipped the pages and found a bookmark. "She also marked the chapter regarding the Wendigos."

"I assume you know what you're talking about."

He nodded, murmuring something. "They're creatures born of cannibalistic rituals, or so I remember. I've read stuff too, but not this book. If I remember correctly, the Wendigo is a monstrous creature that generates from men and women that have consumed human flesh. They would turn into lanky, blind creatures with long limbs and sharp teeth, always hungry for more human meat."

She joined him at the desk. "Creepy interests for a twenty years old girl." She took a file and opened it. There was a map of a mountain, with landmarks scribbled on with uncertain hand. Cabin, Cableway, Sanatorium were marked in red pen, while other ones were written in black. A blue jagged line seemed to mark a road or a path that linked all the locations. "Was she investigating on the massacre?"

Castle shrugged. "Wouldn't you, if you were the only to survive?"

Beckett groaned. "Touchè. It's just… we're so far away, you said it happened in the mountains of Western Canada, and she was from Seattle, what was she doing here?"

"Mr. Roberts said she received some mail, maybe she had contacted an expert in this stuff? You know, with the universities here, there's a chance you can find an expert of Native American myths here."

"Good point, let's look for that mail."

They did find some torn envelopes of various sizes in the trash bin in the small bathroom. Unfortunately, there was no sender address written on them. "Back at square one," she murmured.

"Not really." As usual, Castle had his smartphone in his hands. "There's an anthropology professor at Hudson University that appears to be an authority on the subject in question. Want to call him?"

XXX

While Beckett was on the phone with the professor at Hudson University, Castle received a call himself, from Lanie.

"Castle, where's Kate? I can't seem to reach her."

"She's on the phone at the moment. You got something for us?"

"Not really, I just got at the morgue, I just wanted to tell you that I found her phone in an inner pocket of her jacket and I took the liberty to notify her parents. They'll fly in as soon as they can catch a flight."

Castle nodded. "I'll make sure to tell Kate. Found anything else?"

Lanie sighed on the other side of the line. "Not really. A bunch of crumpled paper in her pockets, a ticket for a Broadway musical that took place a couple of nights ago… not much to be honest, but I'll leave the detective work to you. I'm going to take some x-rays of the body now the proceed with the autopsy. I'll let you know when I'm done."

By the time Lanie hung up, Kate had finished talking to the professor. "Learned anything?" he asked.

She shook her head. "Not really, he only confirmed she had asked him some notions about Wendigos and he provided some material, after she had told him about the massacre. Was that Lanie?"

"Yes, he found her phone and called her family. Her parents are flying in."

Beckett sighed. "I really hope Espo and Ryan have something to work on, because we have nothing to work on here!"

Castle reached out for her hand and pulled her into a hug. They had just come off a very strenuous case that had involved all of them on a personal level and the weariness from that still had to wore off. In fact, he himself had been framed by Jerry Tyson, in a wayward vendetta for figuring out who he was, two years prior. And now this case looked impossible right from the start, not to mention it was incredibly sad that a girl, lucky enough to survive a massacre in which all her friends had died, had to die like that. Castle felt the pang of sadness tightening in his chest, as he thought his own daughter wasn't too younger than Sam, and now two parents had to grieve the death of their child.

"Hey, was there any case we weren't able to solve? Come on, we can make it. And after that, we're going to have the best Halloween party ever, alright? Why don't you call CSU so they can come and do their thing here, and we grab some real breakfast? We can get some for Espo and Ryan too, if you want."

Beckett smiled, briefly. "Sounds like a good idea. Lead the way then."