A/N: Next part! I have screwed with canon slightly, since this is AU, so this fic takes part in Season 1 of Supernatural, just after 'Something Wicked'. I wanted non-jaded boys!

"…let my heart go, let your son grow. Mama, let my heart go, or let this heart be still…yeah, still!"

The dulcet tones of his big brother caterwauling along to Metallica was nothing new to Sam Winchester. Neither was spending hour upon hour cooped up in Dean's beloved Impala as they drove cross-country chasing ghost stories, often with a dangerous sting of truth in their tales. However, this particular journey had him glancing in awe out of the open window. The skyline of Manhattan was…something else. Thousands of high rise skyscrapers jostled against each other as they strained their hulking forms up to touch the open sky. California was huge, no question, but something about taking on a hunt in an area so crammed with buildings and crowds and noise…it wasn't going to be easy.

Dean glanced sideways at him from where he was supposed to be watching the busy New Jersey Turnpike. A large people carrier overtook them, honking their horn loudly. His big brother flicked them the bird almost unconsciously, still scrutinizing Sam.

"…You ok?" he said finally. Sam gave him a weak smile. Their last hunt had been difficult for the both of them, the Shtriga bringing up some unpleasant memories. Sam knew that Dean had been far more affected than himself, but his elder brother was never one to concentrate on his own feelings, especially when he was concerned about Sammy.

"I'm fine, dude. Just kinda overwhelmed. New York is huge!"

Dean chuckled. "Small town boy, through and through. Would've thought Stanford cured you of that Waltons crap."

Sam rolled his eyes. "Whatever."

Dean slapped a crumpled newspaper into his hands. "Here you go, country boy. Make yourself useful, and check up on the facts Caleb gave us."

Sam stuck his tongue out at his laughing brother, and opened the paper. Caleb had called them in Wisconsin a day or so ago, claiming that his usual contact for the East Coast had suffered a serious case of…decapitation, and some "shit was goin' down" in New York. When pressed, their friend admitted that he wasn't really sure what the problem was, but a 'lady friend' had called him after her niece had died three days after sneaking into a sewer tunnel. According to the newspaper Sam was reading, said tunnel had a ghostly legend attached to it that attracted foolishly curious teens like bees to a honeypot.

Apparently, before they died, the afflicted children told anyone who would listen that a mysterious, irresistible voice could be heard calling softly in a certain area of Central Park. The children swore blind that the force sounded like their own mothers.

The article ended with a description of the children currently being treated at the New York Presbyterian; the Morgan Stanley Children's Hospital, to be precise. Sam finished the story with a heavy heart, just as the late afternoon sunlight suddenly dimmed. Dean had just pulled into the Holland Tunnel, and slowed drastically in the slew of traffic. Now that there was no danger of distracting his brother and causing an accident (not that Dean seemed bothered in the slightest, so confident was he in the abilities of himself and his 'baby'), Sam filled him in with a brief overview of what they were to expect.

"So, what do you think is luring these kids into the sewers?" he finished, gauging Dean's reaction carefully. He knew that the cases involving children struck an unpleasant chord within his elder brother.

Dean rubbed a hand over his face, three-day stubble rasping against his palm. "Could be anything. Skinwalkers can imitate human voices. Wendigos too. Central Park ain't exactly a hotspot for angry, cannibalistic monsters, though, so I'm goin' for ghost."

"What about another Shtriga?"

"We couldn't possibly be that unlucky, dude. Anyway, paper said the victims were all teenagers, right? Too old. There's gotta be a Shtriga smorgasbord of younger kids hangin' around a park waiting to get eaten."

Sam wrinkled his nose at Dean's rough statement, but ultimately agreed. Sighing, he took a gulp of stone-cold coffee and shuddered. The head rest provided a comfortable napping spot while his brother attempted to navigate the traffic of a Friday evening in New York City. This was going to take a while.

'My legs are getting numb,' Raphael thought to himself, groaning internally so as not to disturb the sleeping lump curled up on his lap. He wouldn't usually allow such ridiculously sappy closeness, but c'mon, no-one with a heart could have refused Michelangelo that afternoon. After his accident, and subsequent nap in the dojo, Raph's baby brother had been…clingier than usual. Sure, the kid was affectionate; hugs and head rubs and nuzzles were all gratefully received and given by the youngest turtle.

However, when Splinter had gently awoken Mikey earlier that day, he had shied away from his father and followed Raph into the main living area. They had been watching TV relatively peacefully, with Mikey ignoring any and all attempts to participate in conversation, or be aggravated by his immediate older brother, when Mikey suddenly slumped sideways and landed on Raph's lap.

"I'm so cold," was his only explanation, and instead of shoving his little brother onto the floor like he usually would, Raph nodded and pulled a blanket from the back of the couch. Mikey's skin was freezing.

"Thanks," the youngest turtle breathed, huddling in closer to Raph's warmth. The bigger turtle could easily admit that he was worried. Mikey was cuddly, sure, but in a totally irritating, irrepressible puppy-esque manner. This quiet, shivering lump with a bruise blossoming over one eye didn't resemble his bright, cheerful baby brother in the slightest. Hesitating slightly, Raph placed his hand heavily on Mikey's head, which seemed to soothe him a little.

An hour later, Leonardo wandered in with a book in his hand, still damp from his post-training shower. Raph noticed his eldest brother do the slightest double-take when he saw the sleeping Mikey draped over Raph's lap. Leo's inky-blue eyes narrowed in concern.

"Did I really hit him that hard?" he asked, chewing on his lower lip in consternation and approaching the sitting pair at a rapid pace. Raphael shook his head and shifted uncomfortably. Mikey was heavy.

"Nah," he reassured Leo, rolling his eyes when the other turtle plonked himself on the raised flooring behind the couch. Was everyone going to invade his personal space today? "Pretty sure he's coming down with something. He keeps saying he's cold."

Momentarily reassured, Leo slid into the space not currently occupied by their slumbering brother, and lifted Mikey's legs onto his own lap. Raph pointedly turned on the TV to dissuade further conversation. Flipping through the channels, he caught snippets of programmes, none of them particularly catching his attention.

"…love you, I don't care if you're my half-sister!"

"…Un buen día por…"

"…from half-court…"

"…deaths occurring after breaking into the city's sewer system…"

"…ready to win some CASH?!"

"Hold it, Raph." Leo's eyes had lifted from his book, and were squinting at the screen with laser focus. "Go back one."

Raph shrugged, but obliged. The usually jovial face of Carlos Chiang O'Brien Gambe filled the screen, looking strangely sombre as he spoke to a blonde reporter on site at a large, imposing building.

"…here at Morgan Stanley Children's Hospital where another child has, despite the best efforts of the doctors here, unfortunately passed away," she said. "Specialists are as yet baffled by the strange symptoms exhibited by this mysterious disease. My source inside the hospital claims that patients are, for lack of a better term, 'wasting away'. The disease shows all the signs of a terminal illness in its final stages, but is accelerated to a point whereby sufferers are only lasting, on average, one week. My source also commented that many of the patients seemed obsessed with keeping their mothers nearby.

"The only thing that seems to link the deceased together is the fact that they all admitted to breaking in to a disused sewer tunnel underneath Central Park. Experts have examined the area in case of any airborne diseases, but both samples from the tunnel and blood taken from the patients themselves show no abnormalities. We urge you, please, do not enter the tunnel yourself. Security measures have been increased-"

The woman's voice stopped abruptly as Leo pressed the remote. Silence reigned throughout the living area, making the already large expanse of their subway station home seem cavernous. Raphael and Leonardo looked at each other over the sleeping lump of baby brother in both of their laps, fear and confusion evident in both emerald green and navy blue eyes. Leo opened his mouth to speak, and both were startled by the sudden appearance of Donatello and April.

"Guys! Look what April and I just developed! It's an app for tracking…what's the matter?" Donnie's speech gradually trailed off as he came across his three brothers, the youngest sleeping soundly across the laps of the others, who seemed frozen with worry.

"…Leo? Raph? What's wrong?" questioned April, already on the move towards the turtles gathered on the couch. Donatello was on her heels, and they both crouched down in front of their stricken brothers.

Leo managed to find his voice.

"…I think we need Sensei."

"Jeez…" Donnie said, after Leo and Raph had haltingly explained what they had heard. "There's some kind of airborne disease killing people down here?! It sounds a little like tuberculosis! Who knows how long we've been exposed to all the pathogens-"

Splinter interrupted his most intelligent son gently. "Donatello, Leonardo and Raphael have explained that there is no evidence of any disease in the bloodstream of the patients. Calm your mind, my son. It cannot be tuberculosis. Besides, the timescale of this tragedy is reported to have gone on for some time."

They were each silent for a moment, absorbing the words Sensei both did and didn't say. The disturbing fact of the matter was, Donnie mused, that had this supposed disease been lingering in the sewers for a prolonged amount of time, they all undoubtedly would have already contracted it.

"So…what is it?" April broke the silence, her voice trembling slightly.

"…It's Mama," came a halting, weak voice from the couch. Five heads whipped in the direction of the stirring turtle still resting on the laps of his older brothers. Michelangelo's eyes were still closed, but a frown furrowed his forehead, and his beak was scrunched up in either pain or fear. Beads of cold sweat had formed on his face, and his freckles stood out in sharp relief against his pale skin. All in all, their baby brother had never looked worse.

"…Michelangelo? My son, what did you just say?" Master Splinter questioned with a strange trembling note to his voice. "Are you awake? What did you just say, Michelangelo?!"

Their father had, by this point, seized the sleeping turtle by his shoulders, and heaved him from his brothers in to his own embrace. Mikey's eyes opened at once, and he struggled fiercely against his Sensei.

"Lemme go!" he screamed, startling everyone present. The younger members of the clan crowded around their Sensei and their baby brother, each grabbing a flailing limb and attempting, with little success, to calm him.

"S-Sensei! Maybe you should let him go!" April cried, narrowly avoiding a large foot to the face. Splinter took no notice of his newest pupil, and instead, slapped his youngest around the face. With one final shriek of "MAMA-", Michelangelo shot into an upright position, and looked blearily around him.

"…Why's everybody staring at me?"

Dean had felt a little bad about duping the sweet nurse in charge of the intensive care unit at the Morgan Stanley Children's Hospital, but unfortunately, it had to be done. The NYPD database Sam had hacked into had been full of pictures of the terminally ill teenagers. Their wasted bodies and clouded, milky eyes had been more than enough encouragement to get the job done any way possible.

"So, why are you here, Agent…?"

"Roeser, ma'am, and my partner Agent Bloom. We're opening up a cold case; seems like there's been an increase in the fatal activity around a certain area in Central Park."

The nurse's brown eyes widened. Bingo. "You mean the sewers case?" she chirped helpfully. "Yes, we've had more patients over the last six months than ever before. I was new here when it all started six years ago. Horrible. Those poor children."

Dean exchanged a glance with his brother. Sam was studiously scribbling in his notebook, but he gave Dean a surreptitious nod to continue.

"Yes, it must be awful. Do you have any of the affected patients here now?"

The nurse looked away from his probing gaze, sadness clouding her bright expression. "I'm afraid the last one passed on two days ago, Agent."

Dean's heart sank, for the loss of the child and the loss of potential insider information. "I'm really sorry to hear that, ma'am. Has there been any headway in identifying the disease?"

"No, I'm sorry to say. It's like nothing we've ever seen before. No abnormalities in the blood, nothing shows up on the scans…it's like they're just…wasting away."

Dean nodded, and placed a hand on her shoulder, making her jump slightly. "One more question, and I'm sorry if it seems a little cold. When the children…passed on, was it an easy death? Did they go peacefully?"

Her eyes hardened. "No death is 'easy', Agent Roeser," she said coldly. "If it's essential to your investigation, then I can tell you that they died…c-crying for their mothers." Her voice began to shake, and she put a hand up to her mouth.

"You're a brave woman, ma'am. I don't think I could've stood it," Dean said truthfully, feeling Sam's giant puppy-dog eyes gazing in their direction sympathetically. "Did any of the children call for their fathers?"

The nurse acquired a faraway look on her face. "You know, it's the strangest thing," she murmured. "Each and every child went crazy when their fathers got anywhere near them. Even if there was no mom there."

Once more, Dean flicked his eyes to Sam, who had also noticed the significance of the nurse's statement. He ducked his head to the nurse in a short, conclusive nod.

"Thank you, ma'am, you've been so helpful. If you think of anything else, anything," Dean stressed, with prolonged eye-contact, "…call me on this number."

He felt a small sense of gratification as she flushed whilst grasping the crumpled piece of Sam's notebook paper that he'd written his cell number on. The brothers turned to leave, and hadn't gotten more than four steps away when they were halted by her voice.

"Agents…I really hope you find out what's going on. This needs to stop."

Slightly taken aback by the light of understanding in her eyes, Dean floundered momentarily. Sam stepped up, speaking for the first time since their charade had begun.

"Don't worry. We'll make sure it does."

Hurrying out of the large double doors at the entrance to the children's hospital, they both breathed a sigh of relief. Sam turned to his big brother with a questioning expression.

"So, what's our next move?"

Good question, Sammy. The information the nurse had given them, while valuable in determining the nature of the job, had revealed little in the way of hard evidence.

"I'm thinking that it's definitely a haunting; some kind of ghost sickness," Dean mused. "But there's only one way to be sure."

Sam's expression suggested that he knew what Dean was about to say, and was none too pleased about it.

"We need to make a trip into the sewers."