Roy meets House for the first time and Cameron tells him that the tests have come back negative for abdominal epilepsy and now there's a rash on Jack's chest. "That I did not expect," House says. Roy is understandably displeased to hear that from the best doctor in the world and says so. House blows him off even though he's the father of a mysteriously dying child who House and his team have only made worse. Good to see that loss of power is helping House interact with others.
Back in the meeting room, the team is back to square one. Cameron goes for the gold with her diagnosis of both lupus AND vasculitis. Oh, vasculitis, how I've missed you! But Cameron is wrong, of course, because a diagnosis of lupus and vasculitis is going to be the series finale. Chase suggests polyarteritis nodosa, which Foreman turns down. "Okay, you come up with something better," Chase snaps at him. Settle down, Chase. Foreman is your boss (I think) and he can't just accept your diagnosis that doesn't fit because there aren't any other ones. Oh wait -- I guess they will. And it'll mean yet another biopsy for poor Jack, this time from his testicle. Good thing he's in a coma. Foreman volunteers himself and Cameron to do it. Cameron whines that Chase should do it because this was his diagnosis. Foreman says Cameron has a better rapport with Roy, which will come in handy when they tell him that his kid needs more biopsies and from his balls, too. Cameron suspects that Foreman really wants to keep Chase behind to "overprep" for the M&M. Foreman immediately says that's what it is, and Cameron buys it. "Don't be a child," she says. Don't talk to your boss that way, Cameron. House, meanwhile, isn't paying attention to everyone's attitude problem because he just came up with a diagnosis that fits much better than Chase's. Unfortunately, it's Degos disease, which is fatal. House offers to break the news to Roy. That seems like a terrible idea, but no one bothers to stop him because they're too busy worrying about saving their own asses (Foreman, Chase) or making sad faces (Cameron).
House enters the room and tells Roy that they have their diagnosis. The tell-tale sign was the chest rash that apparently spread down to Jack's penis, which is usually the first symptom of Degos but this time decided to hold off for a while. House lets Roy ask him what the treatment for this is before informing him that there isn't one. "You're wrong," Roy says. Which is perfectly reasonable, since they were wrong with the other five diagnoses. But this time, House says, they "re-checked" the biopsies and found it was definitely Degos somehow. Jack will never wake up from his coma and he'll be dead within a day. House says he's sorry, and then he just leaves. I guess he only stays with people and their dying relatives in season premieres.