A/N: I've decided to set this at some point later on in the current season (four) of Castle and late season five of House. That season of House had my favourite team (Foreman, Chase, Thirteen and Taub) plus Cameron, so I'm setting this after Kutner died (not that I don't like him, I just prefer Chase). Timelines are therefore messed up a bit, but treat it as AU and take it with a pinch of salt.

Disclaimer: Last time I'm saying it as it isn't necessary to repeat it every single chapter, I don't own Castle or House.

Chapter Two – Choosing A Case

"House!" The sound of Lisa Cuddy's voice rang out in a harsh tone through the lobby of Princeton Plainsboro Teaching Hospital, her displeasure apparent to everyone in earshot.

Standing at the door to the elevator, Gregory House groaned inwardly to himself and pretended not to hear her. Looking up at the small screen in the wall he could tell the elevator was at the first floor. Just keep up the act a couple more seconds…

With a 'pinging' sound announcing the arrival of the elevator, the doors slid open and House stepped inside. He used the hand not holding his cane to punch the button for the floor and then turned round to watch the doors close. Thankfully, he was only occupant of the elevator and there was no-one else around to hold him up, and as the doors began to slide shut he felt a sense of satisfaction that he'd managed to avoid another tedious tongue-lashing from his boss. It didn't last long however as he saw Cuddy dashing across the lobby to reach him, and just when he thought he was about to get away she reached the elevator and thrust out an arm to stop the doors from closing fully.

It looked like he hadn't avoided her then. But still, she was obviously pissed off with him, and there was some satisfaction to be gleaned from that.

As the doors slid open again Cuddy shot him a death glare. "House," she said again in a very annoyed tone, as if demanding an explanation as to why he'd just ignored her.

He pretended not to notice the way she was looking at him and simply responded with, "Dr Cuddy," as if in formal greeting.

She kept up the glare for a moment longer, but then realising that was the closest she was going to get to polite from him she decided to press on with the reason she wanted to talk to him in the first place. "Have you chosen a case yet?" she asked insistently.

"No," he replied in a tone of complete disinterest.

Cuddy gave him an exasperated look. "House, I gave you those patient files to look at two days ago. I expected you to have picked one of them by now."

"No you didn't," he answered back, "If you expected it you would have asked me which one I'd chosen and not whether I had. You knew I hadn't picked one. That's why you were already annoyed with me before you'd even asked."

"Yeah, well it would've been nice if you'd surprised me for once," Cuddy said, trying not to let him see how much he was annoying her. If he knew he was managing to wind her up that would only encourage him even further. "I can't keep these patients in limbo any longer not knowing what's going on, so just pick one of the cases. Which is it going to be?"

House looked like he might actually be thinking about it for a few moments, and then said bluntly, "Neither."

Cuddy glared even harder, her patience wearing thin. "Neither isn't an option, House," she said, "Why are you being so stubborn about this?"

"Because neither of them is interesting."

"What about a seven year old girl who keeps having episodic bouts of amnesia isn't interesting?"

"The fact that she's seven. Some kids just don't pay enough attention to remember anything that goes on around them. And ten years from now she won't remember anything about being seven anyway."

Cuddy rolled her eyes, wishing he'd just stop being uncooperative for the sake of it. "Take the other case then," she said dismissively.

"A guy with a mysterious rash that won't go away? Why bother? It's lupus."

Now it just seemed like he was trying too hard to be awkward. "It's not lupus," Cuddy responded, not even trying to hide her frustration now, "You think they didn't test for that already? It came back negative."

"Well, the tests are wrong," he replied without a hint of uncertainty.

Arrogant S.O.B, she thought, but what did she expect? "They're not wrong, House."

"Yes they are. The patient was taking antihistamines to self treat the rash, which causes elevated levels of complement C3. If you did the test when he was first brought in that would lead to a false negative. Do the test again."

He perhaps had a point, Cuddy admitted to herself, but there was no way he could be that confident about it from just having read the file. "If you're so sure about it, House, why don't you just take the case?"

"Because there's no challenge in it. It's boring," House answered.

Cuddy was about to respond when a man walked past her and stepped into the elevator, giving her a slightly puzzled look as he noticed she was standing holding the door open. As the man hit the button for the fifth floor House asked Cuddy, "Are you going to use this elevator? Because some of us don't like waiting and we can't take the stairs." He raised his cane and waved it in front of her for emphasis.

Cuddy scowled at him and then shot an apologetic glance at the other man before saying, "Alright, but choose a damn case by tonight, House, or your clinic hours this week are going to be doubled."

She stepped away, allowing the doors to close as she headed off again while House was left standing with the other man, who looked a little perplexed by the exchange he'd just witnessed between them. House turned to him. "She likes doing that," he said as his explanation for what had just happened, "Cornering men in elevators where she knows they can't get away."

The man just raised an eyebrow at him and nodded in a way that suggested he didn't really want to know.

-oOo-

Not long afterwards…

Pushing open the door to the ER and striding inside (or at least striding as much as a man with a limp could stride) House began to navigate his way through the hubbub of the emergency room. He made a point of steering well clear of one of the patients on the left hand side of the room – a youth with oily hair and poor complexion who was obviously just seconds away from throwing up – and made his way to where he could see the blonde doctor in scrubs he was looking for. "Cameron," he called out to get her attention, and as she turned round to see who it was she didn't look at all pleased to see him. "You got a case for me?" he said, not giving her chance to speak first.

Cameron looked like she couldn't understand what he was doing looking for a case in the ER, but decided she'd get rid of him quicker if she just didn't ask. "No," she answered, not stopping what she was doing before and pulling off the latex gloves she was wearing to drop them in a safe disposal container. "But if you asked Cuddy I'm sure she would." She turned her back on him to cross to one of the desks in the room and pick up a patient chart, which she began to fill in.

House followed her, not put off by her dismissive attitude. "She doesn't. I checked."

Cameron looked up from the paperwork and raised an eyebrow at him. "Really? So she's specifically said she doesn't have any cases for you and told you to come and look for one in the ER?"

"No," he answered, "She said she'd got cases for me, but she's wrong. They're no good. Perhaps you can do better."

Cameron just gave an exasperated shake of her head. "I don't know what you're hoping to find, House. Most of the patients here have just been in accidents or had particularly severe allergic reactions. Nothing in your league. You'd be better off just taking whatever Cuddy's offered you."

House didn't look satisfied with that answer, which Cameron knew he wouldn't be, but that hadn't stopped her hoping. "You must have seen dozens of patients come through the ER in the past couple of days," he said, obviously having no intention of leaving her alone until he got what he wanted. "At least one of them has got to have been suffering from something unusual." At that point he reached out to pick up another file from the desk – the patient log – and started to flick through it.

Giving him an irritated look, Cameron stopped filling in her own chart and snatched it off him. "Stop that," she instructed, "If there was anything in there you were needed for Cuddy would have told you already. Why are you so determined not to take one of the cases she's suggested anyway?"

"Because she hasn't suggested any good ones," House said as if addressing a moron, and then reached out to roughly take the file back off her.

Cameron looked like she might try taking it back again, but then just sighed and went back to her paperwork. "Whatever, House," she said, not able to be bothered arguing with him anymore, "But even if you do find anything in there Cuddy won't let you take the case if there's other ones she needs you for."

"Yes she will," House said, "As long as it's better than the ones she's already got. Which won't take much." He started flicking through the file again, talking to himself as he went. "Sudden swelling of the glands…no….Severe cramp in both hands…no…Broken foot through dropping a vacuum cleaner on it? That is completely moronic, but no…"

Cameron continued with her paperwork, wondering when he'd get to the point of just giving up, but was quite surprised when she heard him say, "Right, I'll take that one."

Setting down her pen, Cameron looked up at him with a puzzled expression. He continued to read across the page, paraphrasing aloud. "Brought in last night, where's he now?...Room E63. Right." Apparently satisfied, he appeared to be about to walk away and find the patient he'd just decided to treat, but Cameron abruptly snatched the patient log back off him before he'd even had chance to put it down.

She opened it and scanned for the patient who was down as having been moved to room E63, and frowned in bewilderment when she read that entry. "Seriously?" she said, looking up at House and raising an eyebrow. "Loss of consciousness and asphyxia? That's what's got you interested?"

He gave her a mocking look, as if he thought that was a stupid question. "Cameron, I can't imagine why you of all people think that's a bad reason for me to want to treat a patient."

"I don't think it's a bad reason," she said defensively, "But usually wouldn't a dozen other people have had to rule out the obvious causes before you took an interest?"

He didn't answer her directly, but instead went down the route of trying to get her to work things out, just like he'd done when she still worked for him. "If a patient was brought in with a case of sickle-cell anaemia, would you be interested?" he asked, causing Cameron to frown as she tried to figure out why that was supposed to explain things.

"Well, yes, but no more so than in any other case..."

That was all the answer he needed to hear before he continued to talk over her. "Right, and what if that patient happened to be Tom Cruise? Then would you be more interested?"

She still couldn't understand why he thought this did anything to explain what was so special about this patient. "Um, yes?" she replied a little uncertainly.

"Why?"

He shot the question at her abruptly, and even though she'd gotten used to his ways of liking to make other people feel stupid, Cameron still wasn't sure where he was going with this. "Because white people don't get sickle-cell anaemia," she answered, knowing he was expecting her to give an answer based on the medical abnormality of the hypothetical scenario.

"Wrong!" House said, obviously enjoying the fact that she'd given the answer he wanted. "You'd be interested because he's Tom Cruise. Only a doctor who'd never seen Mission Impossible before would find the case interesting solely because it's a highly rare medical phenomenon."

Cameron's frown deepened as she tried to work out why he was playing this game with her. "But you wouldn't. You'd only be interested in getting an answer. The fact that he's Tom Cruise wouldn't matter to you at all."

House had begun to walk away again and Cameron was following him, wanting to hear the rest of the explanation. "The fact that he's starred in hundreds of movies and is worth millions of dollars wouldn't matter to me," House conceded, "But what would matter is the fact that he's white and shouldn't have the disease at all. And if being Tom Cruise and being white go together, that means the disease isn't the interesting part, it's the person who's got it."

This was almost starting to make sense to Cameron, but there was still a lot about it she didn't get. "So who is the patient then? Am I missing something?"

They'd reached one of the doors to the ER, and as House leant on it to push it open he looked down at her. "Having read some of his books, I'd say you're missing a lot," he said before opening the door fully and walking out into the corridor.

Now Cameron was intrigued. What did that mean? Had House recognised the name in the patient log? Because she certainly didn't. She was almost tempted to follow him out into the corridor and ask more questions, but then remembered she had a job to be doing and there were people who needed her help for reasons other than just to piss off their boss. House obviously had some ulterior motive for taking the case, but she decided to let him go, thinking that even if she was letting him walk away now she was still going to find out what he was up to later.

A/N: I said I was going to make a point of doing proper research for this story, but it's been incredibly difficult and I've still taken a few liberties. I have no idea if antihistamines actually would cause elevated levels of complement C3. I couldn't find any sources that showed any relationship between them, but lupus would be tested for by seeing if the patient has a low level of complement C3 in their blood. Therefore I think the explanation I've given makes partial sense, but I still feel like it's something I could do better on and I'm going to make sure I continue to do research for it so I can rewrite it at some point. Since I didn't want the story to grind to a halt because of that one small point I carried on anyway, but I now have to respect the writers of House even more for managing to make everything accurate.

Another thing I didn't anticipate when I started writing this was just how hard it would be to get House in character. I think what I've done is passable, but I still feel like I could have done better. I'm also concerned that this chapter got a little convoluted towards the end, but writing for House has been even harder than I expected! I'll have to see if I can work on improving.

Fun story I wanted to share: I live in a city with a castle. I was on the bus earlier and going past the end of Castle Street I saw a building called 'Castle House'. Made me smile :)

Anyway, I hope you're enjoying this so far and I'd love to know what you think!