The man who walked into Dr. Lisa Cuddy's office was of small stature and probably blended into a crown easily. He was walking with a slight gait in his left leg, had on a harmless sweater and was smiling awkwardly as he rapped on the door with his knuckle.

"Hello? Dr. Cuddy?" He inquired politely.

"Yes? Do you have an appointment?" She quipped.

"No, er," The man brought a hand through blond-gray hair, military short. The door shut quietly behind him. He had a distinctive British accent. "This is about Dr. Gregory House."

"Oh, god. What has he done this time? If you are here to file a malpractice suit, I can get you in touch with our attor-"

"No, no!" He insisted, striding forward to stand at parade rest in front of her desk. "Nothing like that at all, though I can see why you'd automatically jump to that conclusion. My name is Dr. John Watson."

Cuddy stood and calmly shook Dr. Watson's hand over her desk as he continued, "My partner and I work with the Scotland Yard Police Department in London. Homicide division, actually."

Cuddy's face turned pale as her mouth unconsciously tightened, "That's not reassuring."

"Greg's not in trouble or anything," Dr. Watson replied, giving a quirky half-smile, "We actually need his help on a case we're working on.

"Okay…" Cuddy didn't really see where this is going.

Dr. Watson pulled a manila folio from under his arm, handing it towards her. She flipped it open with easy grace, blue eyes scanning the information. It appeared to be meticulously-detailed autopsy reports of violent murders. Rather disgusting stuff about post-mortem brain transplanting.

"There's a serial killer targeting victims just outside of Brixton in London," Dr. Watson explained. "He's performing lobotomies on the victims and apparently somehow keeping their brains alive outside of their skull. We have no idea how he's doing it. We know this because the murderer has been sending us complex neuroimaging of the functioning… Frankenstein brain is what we're calling it. Greg's medical expertise might be invaluable in helping us track down this person before he strikes again."

"You know the murderer is a he?"

"Statistically more likely." Dr. Watson stated as though it was an afterthought. "So, I wanted to bring it up with the head of the hospital before I let Greg know about the case. This is the sort of puzzle that he'd refuse to back away from, even without permission."

"So you're asking permission. What can he do from here? He has another case right now you know, and many clinic hours to make up."

"He can tell us quite a bit," Dr. Watson said, taking the file back from Cuddy. "I have with me all the materials accessible by Scotland Yard plus dozens of samples from the crime scenes in biohazard containers out in the parking ramp. I was planning on signing them into your intake desk, if you give me your permission. My partner is probably at the St. Barts morgue right now, examining evidence from the autopsies. We'd only need a few days of his time."

Cuddy's eyes narrowed, "What exactly do you and your partner do?"

He looked a little chagrined, "My partner is a consulting detective and I work as a consulting doctor. The only ones in the world actually."

Cuddy sat behind her desk and steepled her chin on her twined fingers.

"And you will be around to supervise him? I'll need paperwork from Scotland Yard confirming your story."

"Yes to both." Dr. Watson grinned. "Plus with this case maybe Greg won't cause too much trouble this week!"

"You call him Greg," Cuddy mused. "Nobody calls him that. Not even his best friend. How do you know Dr. House?"

"He lived with us for a while, what was it? Thirteen months ago?"

"What? Really?"

"Yes, it was after he was in that rehab facility here in America. He went on sabbatical after and spent four months in London solving crimes with us. Kept him busy while he got over the longterm effects of withdrawal."

Cuddy did the math and knew exactly what "sabbatical" he was referring to. It was during that dark time where House had just OD'd, Wilson was refusing to talk to him and to top it off he was in danger of losing his medical license. She'd never known where he went off to during that time, just that when he got back he'd looked better than before and was able to work again.

"All right, Dr. Watson. Permission granted. Please file all paperwork on the second floor, I'm sure one of House's fellows will assist you in locating it."

"John,"

"Pardon?"

"Please just call me John." This strange British man said sheepishly, "I may still hold my medical license, but I'm more of a hired gun nowadays than an actual doctor. I work sometimes at a clinic by our flat, but nowhere as fancy as this fine hospital."

Cuddy smiled, "Well, then, John. I suppose you'll be off to tell him, then. Do you know where his office is?"

"Yes, thank you for your time, Dr. Cuddy."

Well, this should be interesting, she thought, turning back to her paperwork.

As John walked towards House's office, he smiled when he caught glimpse of his friend screaming bloody murder from behind a glass wall. You couldn't hear what he was saying, but he was jabbing a dry-erase marker at a white-board and glaring accusingly at three doctors who sat around a table.

Sighing at the theatrics, he knocked on the door as he pushed it open and heard House snarl, "I'm rather BUSY-" before the grumpy doctor cut himself off and blinked in surprise.

"John? What the hell are you doing here?" House asked incredulously.

The three other doctors turned their necks in unison to stare at him.

John held the folder aloft, "Got a case for you, Greg. Thought this one was right down your alley."

House frowned distrustfully, "A case that's so important you came all the way from London to have me help?"

John nodded, tossing the file in front of him. "Sherlock thinks it's a 9/10 if that's any indication.

The file was snatched open as he scanned the info, his gloomy expression quickly morphing to undisguised glee and interest.

"Oh, John- you didn't!" House crowed as he crowded next to John and gave him a 'manly' one-armed hug, "And Sherlock said you were just terrible at gift-giving."

The former soldier rolled his eyes, "Yeah, well, his list to Father Christmas is rather different from normal blokes. Anyway- I've got the scans on my laptop in my rental."

"But we don't have the actual zombie brain?" House inquired, thumbing through the reports and speed-reading.

"Unfortunately not. The last victim was discovered at fourteen hundred hours yesterday afternoon, same condition as the others. The murderer sends us updated scans every two hours, and we know when to expect another victim because the gray mass is growing. He's weaving lobes of the brain together and the synapsis are still responding. It shouldn't be medically possible,"

"Whose this?" The blond doctor sitting at the table pipped in at the first chance he got.

John smiled at the group, "Sorry, yeah. I'm Dr. John Watson, an old friend of Greg's."

"John! Nobody calls me Greg, you know how much I hate that." House whined petulantly.

"And it's one of the very few things that actually makes you uncomfortable." John confirmed, "Why else would I do it?"

A scowl was the only response given.

"I'm Chase," said the man with a thick Aussie accent. "And this is Thirteen and Masters."

"Pleasure to meet you." John motioned to the file and continued, "I work with the Scotland Yard sometimes. The easiest way I guess is for me to tell you what's going on. Those reports don't say much and are relatively convoluted."

House walked over and grabbed a cup of coffee for John as he took a seat at the table. Chase was watching this with something akin to awe. House never got coffee for other people. And this Dr. Watson called him by his first name (even despite the fact it was obviously done to annoy House, still).

"Did you already go through my handler, then?" House huffed as he dropped the mug on the table.

"Ta," John murmured, "And yes. Dr. Cuddy has already approved your involvement in this case. But first things first…"

John pulled an iPad out of the bag at his side and flipped it on. After scrolling for a moment he brought up a form and handed it to Chase.

"Each of you will have to sign this, it's police procedure. I know that as doctors you are already aware of patient confidentiality, but these forms are a little different. This states that you will not sell any information to the press or discuss the case with others until after we catch the serial killer. Then you can have at it."

"Serial killer…" Thirteen breathed, sounding a little wary as she signed the next form.

Masters handed the iPad back to John, who nodded his thanks. House crossed his arms and stood over by the window in the office, waiting for him to speak.

"Alright, so here's the situation. Five girls, four bodies, all between the ages of seventeen and twenty-four were taken from their homes in the last week and a half. They all lived alone, nothing in common outside of the fact they were students at a local university with outstanding grades. After the second victim was discovered and linked to the first, we discovered a proxy server hidden in the police archives. This link was sent to the head of the investigation, and to my partner."

John turned his iPad to face the three doctors and tapped play. A neurological scan was showing a set of mismatched frontal lobes displaying activity. He scrolled to the next screen and the brain size grew, then to the next. Each time the brain showed more complex activity and seemed to almost be functioning as normal if you weren't looking closely.

"So this guy lobotomized the brains out of one of his victims, then mismatched four different brains and sew them together to somehow form one functioning unit. Right now it's missing its cerebellum, basal ganglia, thalamus and hypothalamus. Which also should be medically impossible, since the brain can't function like that… but, that's the puzzle I bring to you, Dr. House. Figure out how this brain is working, what drugs this guy is likely to be utilizing and what the finished creation could possibly be used for. The information you provide could stop this guy from murdering others and maybe save the person acting as the host, though that's very unlikely."

"But we don't have access to the… patient," Masters said, unsure of her wording. "Victim" seemed a little callous.

"No, but you have preserved samples of each brain utilized and you'll have every record in Scotland Yard's database at your disposal."

"How far has your genius detective gotten?" House quipped, curious.

"He's frustrated," John remarked hesitantly.

"He's so stroppy that you came here to ask for help when one of Mycroft's mules could've done it, isn't he?" House answered knowingly.

John sighed and took a sip of coffee, "Not quite, but close. It was this or accidentally strangle him to death over his microscope at St. Barts. I have Molly on food watch for him during the days I spend here. Bloody berk. But I came because only a doctor, and also trusted soldier of her Majesties finest, can bring such sensitive human remains and other evidence across an international boarder without so much as batting an eyelash."

"On the other side of the ocean," House added, whistling. "Through American security."

"Precisely. Anyway, the samples are locked in a freezer-case in the car. Shouldn't leave them there for too long." John reached up to clutch at his shoulder with a frown before adding, "I'll need help will the cases, got a bit of a bum shoulder if you will."

"Bullets will do that to you," House agreed.

Chase stood, "I'll help."

Masters and Thirteen both shot to their feet also.

"Hey, ladies, I think the big bad Aussie can take care of a bio cases." House snarked, "You both are going straight to the lab to work on our other patient. You know? The one bleeding out of her eyeballs?"

John and Chase walked down the hall amiably to the elevator in silence. As soon as the doors closed Chase glanced over at him.

"You've got questions." John remarked, amused.

"Um, well, so how do you know House?"

"Old friend. Well, actually he's second cousins with my partner."

"And your partner is?"

"The one and only Consulting Detective, Sherlock Holmes."

Chase stood quietly for a moment, then gaped at John as they both started walking down the parking ramp.

"You're THAT Dr. John Watson? The blogger? When I was in med school I'd read your blog every week! Then you took that three year hiatus and all."

John sighed, obviously finding the subject distasteful, "Yeah, hiatus."

He popped the trunk to the rental car, Chase moving to grab the large metal containers with biohazard logos on them. John also threw a large black bag around his waist and grabbed a smaller black box from the front seat.

"Bloody American cars," John mumbled, fumbling with the keys.

"Suppose it's a bit of an experience driving opposite," Chase affirmed. "Happened to me for a while after I moved state-side. You get used to it."

"Well, theres that and the fact that I don't drive much. We work primarily in London so we mostly just take cabs."

"So Sherlock Holmes is House's second cousin?" Chase mused after a minute of companionable silence.

"If you met Sherlock you'd immediately see the resemblance."

"They look alike?" Chase inquired.

"No, except the eyes a bit. Their personalities are scarily similar. You work with Greg, but you don't live with him. Imagine two of them in the same flat."

"He lived with you guys? When? After med school? He's been working here for like ten years."

John smiled, "Last year for a couple months. I'm sure you know what time I'm talking about."

Chase flinched, and nodded, not meeting the other Doctors eyes.

"Best not to bring it up then, ta? Bit of a not good subject for him." John softly said, "You can gossip to your fellows but House is a private person."

"We know that." Chase affirmed. "But even if he is the biggest dick I've ever met, working for him is never boring."

A burst of laughter erupted from the older doctor as they headed to the intake desk to record their samples in the database.

"What?"

"Oh, nothing." John grinned, "That's just something I've said about working and living with Sherlock, is all. It's never boring, indeed."

Chase took the samples to the lab they used the most as John filed paperwork. Masters and Thirteen were there, talking. They turned in unison.

"So what did he say?" Masters asked, not really wanting to pry but also very much wanting to pry.

Chase sighed, sitting on one of the small round chairs in front of a testing unit, "Just that House is related to Sherlock Holmes. Second cousins."

Both women's jaw dropped. When the scandals of Sherlock Holmes were occurring in the UK, many American outlets also covered the sensational tale of the rise and fall and resurrection of their top sleuth.

"How in hell did that come up in your idle conversation?" Thirteen asked in disbelief.

"Holmes is Dr. Watson's partner."

"Oh my god, House said his name earlier." Masters whispered to herself. "But I guess that makes sense since we're going to be looking at a gruesome… serial killing investigation, isn't it? I feel like this is a little out of my depth.

"The patient is still alive, from what Dr. Watson said," Chase reasoned. "Maybe we can save her?"

"After having her brain lopped off, and sewn together with other people's brains? Yeah, maybe in Mary Shelley's nightmares." Thirteen quipped.

"Hence why I've been calling it the 'Frankenstein Brain'" Dr. Watson walked casually into the lab with a smile on his face. "I have to go have a long chat with Greg, I'm guessing you can get started on the samples here?"

The three nodded.

"My recommendation is to check over the stuff Sherlock already examined, but do all the tests anyway even if it's just to make sure the results are the same." Dr. Watson remarked, pulling out a thick file.

"He's a bit anal retentive about taking notes, but some of them might not make sense," John admitted ruefully. "When he's in deep thought, he reverts to latin shorthand. Even I can't decipher it half of the time.

"What's he like?" Thirteen piped in, wondering if she was being rude.

John snorted, shouldering his bag again, "You've met Greg. Just imagine Sherlock as a British version of Greg only less about medicine and more about death and murders. Oh, and less inclined to steal your lunch. Good luck, Doctors."

John leaned back into the chair behind House's desk, nursing his cup of coffee.

"How have things been?" He inquired absently.

"Idle chit chat, John? Really?" House snarked.

The former soldier shrugged amiably, "If you want to talk about work right away, that's fine too."

House propped his chin on his hands, "I suppose that's what you and Sherlock still do. All the time. Every day. When he's not in his damn mind palace."

"Well, that was before we got engaged." John admitted, a shy smile splitting across his face.

"Congrats on that by the way," House grinned wolfishly. "You are seriously more insane than I'd ever could have imagined."

House swiveled in his chair, "You forgave the unforgivable after The Fall."

John nodded ruefully, "I did. And I always will."

The consulting doctor paused for a long moment, staring out House's office window, "I was so alone, and I owe him so much. I plan to marry him and catch bad guys with him and learn everything I can about the science of bloody deduction with him until we decide to retire."

"Then what?" House was honestly curious.

"We'll move to Sussex and he'll keep bees and I'll write the next great British novel. If we don't die in some horrific way, first."

"Of course." House chuckled, shrugging, "What are Sherlock's percentages on that?"

John opened his mouth to reply but a knock on the door had him turning around.

Wilson's head popped into House's office. He glanced at John for a fleeting moment before asking, "Lunch?"

"Can't, got a new case."

"I thought you already had a case. The girl whose bleeding from her eyes and anus? The 'better bleeding virgin Mary theory' as you called her before?" Wilson retorted.

John barked a laugh at that one and stood, "Hullo. I know that Greg's rubbish at introductions. I'm Dr. John Watson."

They shook hands but Wilson stared at him blankly before seeming to return to himself, his tone was stunned as he incredulously sputtered, "I'm Dr. James Wilson. You call him Greg?"

"I've told him to stop!" House whined, loud and catty.

John smirked, "You know damn well why I get to call you Greg."

House glared, "That was blackmail, John. You and your damn fucking fiancé blackmailed me and I don't appreciate being threatened by my own family.

"Family." John echoed sarcastically.

House crossed his arms to pout.

Wilson stood, staring blankly at the both of them, trying to understand what was going on but deciding it wasn't worth it, "Um… I guess I'll catch you later."

He left without another word.

John looked back at the taciturn diagnostician. "Is he your friend, the one who stopped talking to you?"

House nodded, "Yeah, he's the one I told you guys about. After I got back we eventually became friends again. It took a while, but…"

"He forgave the unforgivable?" John repeated wryly.

"I guess so." House mused. A moment later he broke the silence with a fierce grin, "So, let's discuss this serial killer. Ten points for originality, I'd say."

"To be honest, this is one of the barmiest cases I've ever seen," John remarked as he dropped back into the chair. "I mean, Sherlock is about as baffled as I've ever seen him. Besides, er– with Moriarty of course."

"Of course," House frowned. "It will take a while for my team to get through the samples, especially if they are trying to reference Sherlock's crap handwriting. What else can you tell me?"

"Well," John began, "The bodies were found in impeccable condition, minus the missing lobes of brain. The cuts to the skull were professional, surgical, as if for a medical procedure. Bone saw, stainless steel, non-perforated edge. No signs of sexual assault, no struggle. Tox screens came back with trace amounts of benzodiazepine derivatives in their system, administered via injection behind their ear."

"Behind the ear?" House echoed doubtfully, "That's the stupidest spot for an injection site, ever."

"Well, sure, for medical doctors it would be nonsensical. But we're talking about a serial killer. Slam the needle right down the posterior auricular vein and you have not only a hidden injection site but also an unconscious victim in ten seconds flat. Most people don't think to check-"

"Yah, okay, I get that part, clever injection site. But c'mon, those drugs would immediately impair the pristine brain he was trying to lobotomize and experiment on. We'll have to consider other drugs that he could have used," House tapped his fingers rhythmically on his glass desk. "Some types of biocides might not show up on regular tox screens. We'll need that information when determining how he is keeping the host brain alive."

"Sherlock's been searching for more subtle signs in their organs. He's done autopsies on each victim three times by the time I left London. He's ruled out most poisons and doubts it would have been an over the counter medication."

"Why not?"

John shrugged with an eye-roll, "He deduced it, hell if I know the particulars. I'm the medical doctor, but he still treats me like the greenhorn."

"Give me some details on the victims." House responded, ignoring John's complaints.

John huffed but pulled out his iPad and flicked the screen on.

"First victim, Sophie Emerson, 20. She's the body we haven't recovered, the host. She's a entry-level worker for an Alzheimer's Society but taking classes on the side. Second victim, Dafiya Quadeer, 17." John sighed sadly, his face crumpling slightly.

"Dafiya was a honors student who had a part-time job at a convenience shop. Third, Una Illingworth, 23, she was a graduate student at King's College, getting her degree in political sciences. Fourth, Madhu Emani, 24, she worked in her families shawarma restaurant while going to school. And the most recent victim was Dana Edelstein, 21, a full-time researcher with the university."

"Well, I'm sure Sherlock pointed out-"

"That the next victims will be eighteen, nineteen or twenty-two years old, yes. Not really a lot to go on to narrow down potential targets."

"Were all of them sexually active?"

John shook his head in negation, "No, one of the girls was not. Three others were on the pill and the remaining girl had an Implanon birth control still intact in her arm. Sherlock's created his macabre board in our flat trying to discern things that tied the girls together outside of the glaringly obvious."

The former soldier sounded frustrated as he continued, "So far the only thing we've noticed is that they all received good marks at the same university, lived alone within a commuting distance of campus, had stable families, no mutual acquaintances, are of varying ages and ethnicities and have no criminal history to speak of. They didn't even have the same hobbies, none were in the same clubs."

"How big is the student body?"

"Around twenty-five thousand students."

House let out a low whistle.

They sat in a companionable silence for a moment as they mulled over the case.

Unsurprisingly, House broke it.

"So I'm assuming you want to stay with me while your here?"

John nodded sheepishly, "That would be lovely. I could get a hotel, but I get the feeling I won't be spending much time there and it would be a waste of money."

"Doesn't matter, it's fine." House paused, "You do know that I live with Wilson now, don't you?"

John's eyebrows shot up on his forehead, "Really? Oh, then I shouldn't intrude-"

A snort emitted from the taciturn diagnostician, "You're not intruding. If anything, I get the feeling you and Wilson will get along splendidly. You can make tea together and talk about good ingredients for pasta salad."

"So are you two…" John hedged.

"None of your business."

"Okay, none of my business despite the fact that I might accidentally walk in on you-"

"No, no, nothing like that." House cut him off. "Wilson's my best friend. He's dating an idiot nurse from radiology right now and is decidedly hetero. So hetero in fact that he has three alimonies each month. "

John snorted, "You'd be amazed how little sexuality matters when you fall in love."

"Well maybe for you, though I don't think you're a good control group to glean data from."

"Especially for me. You've always been gender blind, Greg, you told me that. I wasn't. I was convinced that I was straight, no question. It was only a heartbeat after he fell that I realized how much he meant- means, to me. And I thought he was dead. I thought he committed suicide."

"Oh god, you're going to get all dramatic and nostalgic to prove a point, aren't you?" House demanded nastily.

John twined his fingers on his lap and continued as if he hadn't heard, "I used to go to his grave and plead to his tombstone for him not to be dead. And you know what?"

"You got your wish," House postulated flatly. "That idiot genius showed up, you bounced into his arms, reconciliation, happily ever after."

"Partly," John chuckled, the sound he made was regretful. "I did get him back, but I broke his nose on my fist as soon as I saw him. Ruddy prat didn't even apologize. He just told me he did it to protect me. I refused to talk to him for over two months. I was so furious, especially now that I knew I'd been in love with him. I wasn't sure if I could ever forgive him for making me watch him jump."

House bit his lip, "But you weren't in love with him when I was in London. If anything, you act how Wilson and I act. Completely platonic."

"We weren't lovers, back then, yeah, but can you seriously say our relationship was completely platonic?" John asked rhetorically. "Sherlock and I have always been… unhealthily co-dependent."

House thought back to the months he stayed in London. Dark days that he wished he could forget. Wilson was gone, he was practically unemployed and about to lose his medical license. It had been hell to start with, the withdrawal, and it was lucky Sherlock was a right bastard because House had been absolutely vicious.

But whenever House went after John, snapped at him or ridiculed him, Sherlock had shut him down so quickly it made his head spin. He'd never known his cousin to be so protective of anything besides his violin.

It was never because House didn't like John. He was actually indifferent about the man in general at first, except to find it odd that Sherlock attached himself to this commonplace doctor. But he'd been lashing out at the only people he could to try to force away the crippling loneliness and boredom and ache for suicide.

Then Sherlock invited him to Bart's for a case and he was suddenly working again, and it wasn't the kind of puzzles he normally craved but they were puzzles anyway; albeit fascinating. John and Sherlock lived in an adrenaline fueled dangerous world. This pair didn't just complacently accept their fate; they embraced it, thrummed alongside disorder and chaos as if it was a natural and erroneous routine.

House had long since admitted to himself that he admired Sherlock and John for their respective assets.

John's wry chuckle shook him from his thoughts. He'd obviously remained silent for too long.

"And your point, being?" House snapped, but his eyes gave away his unease. "I confess to him and ta-daaa, just like you, he becomes magically bisexual and we fall into romantic bliss?"

The smaller doctor's smirk softened into a smile and he opened his mouth to respond, but House's office door opened.

"Well that is the weirdest thing I've ever seen," Chase announced.

Masters nodded, "The readings are all over the place."

John frowned as he turned in his chair, "What do you mean?"

"We were watching the videos of the brain and their synapses while waiting for results, and Dr. Holland was in the lab so we asked him what he thought," Thirteen murmured.

House glared, "Couldn't think of something by yourself?"

"Well, we didn't tell him that it was a… whatever it is." Thirteen continued. "We just asked what he thought, and told him to ignore the missing bits. He said the first thing he noticed was that the synapses reacted as if the brain was being constantly assaulted by pain."

John blinked, surprised. Sherlock hadn't mentioned that.

"When looking at how the individual lobes react to one another, it varies, right? Almost looks like it's working properly?" Masters cut in. "But if you look back at the whole thing, the parietal lobe is lit up like a Christmas tree. I have no idea if the, um, victim can feel this pain, but if she can it's likely torture."

John rubbed his hand over his mouth with a grim nod. "Well, it's on our end to find this guy. What I need to know is if there were any other drugs utilized."

"We could debate it till our faces turn blue," Chase remarked, "But we won't be able to tell much without the… victim."

House cleared his throat, "How's our other patient? The anus-bleeder?"

"She's going through her second round of Inderal to clear up her varices. Her optic nerve isn't as swollen and her blood pressure is stabilizing."

"How's the kidneys?"

"Looking better now that we took her off of the Naproxen."

"Alright, I want Chase in charge of the bleeding girl. Masters, Thirteen, you're going through the Physicians' Desk Reference, starting with the letter A, and you're going to find drugs that could assist this serial guy."

Thirteen's jaw dropped, "That's a shot in the dark!"

John bit his lip, "Maybe, but with the killers schedule, the next victim should show up on the videos in three hours."

House glanced at the clock, "Midnight, every time?"

John nodded his affirmation.

Chase frowned, "But it will only be five."

"London time." John mentioned, pulling his phone out of his pocket. "I'm going to check in with Sherlock, then I'll come back and help you two with your research."

TBC.