"Margaret" wakes up to House hovering over her. He says he has good and bad news: the bad news is that her stomach problems have spread to her heart. But the good news is that she is one young-looking sixty-five year old. Margaret's face says "oooh ... busted." Husband Billy has no idea what's going on. Margaret comes clean: she was married five years ago to an abusive drug addict. Despite running away from him and getting restraining orders, he kept tracking her down, breaking her ribs and poisoning her dog with pesticides. So she bought a new identity and moved to New Jersey. This even explains why she lied about being in Summit when she was in Trenton, as she attends a battered women's support group at Trenton General. There's no battered women's support group closer to home? Weird. Billy wants to know who this guy is so he can go beat him up, but all Margaret will reveal is that his name is Carl. Margaret's real name, she claims, is Jenny.
Anyway, her heart problem rules out their hepatic fibrosis diagnosis, so it's time for another differential diagnosis session. This time, House promises to be fair to Dr. Kelly and not make her nervous, like Chase accused him of doing last time. House accomplishes this by having Dr. Kelly sit directly opposite him in a setting that should remind her of her psychiatric residency days. That, or an episode of $100,000 Pyramid. Dr. Kelly's new diagnosis suggestions are quickly ruled out, although they don't sound any worse than what the other Cottages give. Foreman, however, thinks Dr. Kelly is stupid and will never come close to a good diagnosis and that this is a waste of time. Chase asks him if he has a better answer as House guides Dr. Kelly to connecting Margaret's abusive ex, the open front door, and the fact that her symptoms began after she ate. When she still can't figure it out, he gives her a final hint: it rhymes with "moison." I must be dumb like Dr. Kelly because my first thought was that this was leading to some kind of hoisin sauce allergy and not poisoning. Dr. Kelly is also incredulous, using her psychiatry knowledge to say that Carl would follow his pattern and beat Margaret, not poison her. House points out that Carl totally poisoned the dog, so that kind of is his pattern now. "Oh ... right," Dr. Kelly says. Foreman wants to start treating Margaret for pesticide poisoning. House agrees. Dr. Kelly wants a hole to open up beneath her so she can fall in there and die.
Foreman and Chase share an elevator so Foreman can accuse Chase of hiring Dr. Kelly to sleep with her. Chase says if Foreman is so interested in his life now, they should go bowling. Chase loves bowling! He says he interviewed Dr. Kelly and she was smart and qualified. Foreman doubts this, saying that she got only decent grades at an only decent med school. Yeah, and Foreman was on academic probation when he was in med school. So what? Chase says that Dr. Kelly was the editor of the Rutgers daily newspaper as an undergrad, which really isn't as impressive as Chase thinks it is. But I guess it shows that Dr. Kelly is well-rounded? "You saw what you wanted to see," Foreman says, not convinced.
Billy is not happy to hear the latest theory on what's wrong with his wife, as it involves the ex-husband he didn't even know about breaking into their house and trying to kill her. Margaret apologizes again, but Billy leaves.
Cuddy finds House in the Clinic and asks him about his masseuse. House says her name is "Brandi." He didn't say if it was spelled with an I or a Y, but I think I'm right on this one. Cuddy says that Brandi seems "a little bit slutty." Why, because of her outfit, Cuddy? Because you wear stuff like that at work, too, so you probably shouldn't judge. House says that makes sense, as Brandi is a hooker. "Did you have sex with her?" Cuddy asks. You probably don't want to know the answer to that question, Cuddy. House says he didn't last night, as he is in a committed relationship with Cuddy now. Before that, though, House used to receive a "massage plus happy ending." EW. I mean, I know it happens, but you don't admit it to your girlfriend! That's such a turn-off. I don't know if House is just clueless or pretending not to notice Cuddy's horrified expression. He says Brandi is the only massage therapist he's ever had who actually makes his leg feel better. I'll bet. Cuddy demands that House call her physical therapist and get all future massages from her. House doesn't want to, because he's an asshole and seriously the worst boyfriend ever. Well, except for Carl, although he isn't real so he doesn't count (spoiler alert!). Cuddy says she will not see House until he agrees to stop seeing Brandi. Way to get poor Brandi fired in this tough economy, Cuddy. She could at least give her a job on her team of nannies.
Chase gets ready to leave for the night and finds Dr. Kelly hovering over several medical textbooks in the meeting room. She says she's feeling a lot of pressure. Chase says she should be okay with that, since she was the editor of her school paper and all. Oh, yes, the pressures of getting that school paper out. That's totally the same. Dr. Kelly kind of forgot that she put that on her résumé, apparently, as she quickly tells Chase that she was not, then explains that she wasn't the "editor-in chief," but just an "editor," which is apparently what all the writers on the Rutgers undergrad paper call themselves. Really? Because my school's paper didn't do that. There were editors for certain sections, but not every writer was called an editor. Then again, this is House, where almost every writer and even some cast members double as producers. Dr. Kelly asks Chase if he only hired her because of her undergrad newspaper creds and he's now having "buyer's remorse." Chase denies that he is, but tells her to review the second volume of an infectious disease textbook. And then he gets a page telling him that Billy is in the ER.
House walks into Wilson's apartment both for some love advice and to make use of that set they spent so much money on. He presents Wilson with a hypothetical situation: what if Wilson had a really great handyman who he also had sex with in the past? Would Sam make him stop using that handyman? Wilson already knows what House is talking about, though, as Cuddy is a tattletale. His suggestion to House is to just give in to Cuddy's demands, whether he thinks she's right or not. "This is a point of principle," House says. "Right. You're the Rosa Parks of hooker massages," Wilson says. Well, better that than being the Claudette Colvin of hooker massages. House thinks that if he lets Cuddy be "irrational" (which she isn't being, by the way) now, then she'll be that way for the rest of their relationship. Wilson says that's what relationships are about. "Relationships are hard. You have to make sacrifices," he shrugs, "go get her a gift and apologize." House brightens at this suggestion and takes off, which tells Wilson that House is going to do something ridiculous.
Chase and Dr. Kelly make their way down to the ER. Chase tells her to start "thinking" like House and see whatever's wrong with Billy as something related to whatever's wrong with Margaret. Dr. Kelly says that could be it, but it could also just be a coincidence, thereby not thinking like House at all. In the end, what's wrong with Billy is that he got his face smashed in. He says he found an address in Margaret's book for a guy named Carl in Brooklyn and went up there to confront him, assuming he was the evil ex. He then learned a valuable lesson about why you shouldn't confront someone from Brooklyn. Carl ended up not pressing charges, but he convinced Billy that he was never married to Margaret, had no what she was talking about, and only knew her because they used to work together. And then Billy apparently drove back home to New Jersey while bleeding from various face wounds and went to the PPTH ER. Meanwhile, Foreman calls Chase to inform him that Margaret is now running a fever, which means she wasn't poisoned after all.
Back in the meeting room, House entertains the group with a joke about Carlsbad Caverns and how Billy would try to beat that up if he found it in his wife's address book, then moves onto the slideshow portion of the differential diagnosis of Chase's mental issues. "Meet your doppelganger!" House says to Dr. Kelly, only to show her a slide of a foot with something horrible going on. House apologizes for putting the wrong slide on, and switches it to the correct one: a picture of one very young Chase and an older woman who must be his mother. And whose face has been photoshopped to resemble Dr. Kelly's. "That's baby Chase and his mum! That's adorable!" Taub says. It is, until you remember that Chase's mother drank herself to death when Chase was still a child and then it becomes kind of sad.
Taub says there is a startling resemblance between Mama Chase and Dr. Kelly, and House says he can see why Chase would want to have sex with his mother, because she is hot. Foreman tells House to stop, because he's wrong about this. "You're wrong," Chase says, referring to his and Foreman's earlier conversation in the elevator. House, though, takes this to mean that Chase is admitting that he does want to have sex with his mom. Dr. Kelly finally speaks up to say she's going to assume that Chase hired her because she's good at this job, and proves it by confidently guessing Legionnaire's disease, citing the nasty old air conditioner Taub saw in Margaret's house as the cause. Foreman says that's impossible, since Margaret's lungs haven't been affected. But Dr. Kelly has an explanation for that too, saying that if Margaret was dehydrated enough it would somehow mask the symptoms of pneumonia. House likes this and sends them off to pump Margaret full of fluids and treat her for Legionnaire's. Oh, but wait -- Foreman notes that Taub never wrote anything about that air conditioner in his notes, nor did he tell Dr. Kelly. He did, however, tell Chase about it. Dr. Kelly admits that Legionnaire's was Chase's idea. When Dr. Kelly makes a sad defeated face, House says you can really see how much she looks like Chase's mother.
Chase confronts Foreman on the stairs, asking what his problem is with Dr. Kelly. Foreman says he just doesn't want someone on the team who's unqualified, especially since Foreman will be the one stuck with the brunt of carrying her deadweight since he's sort of kind of Chase's