But wait! House has quit (yet again), and Foreman has replaced him as head of diagnostics. House says he needs to quit because the hospital reminds him of his old life and old habits, so he needs to break free and do something else. Although we all really know that House will be back eventually, because what's the point if he's not? Anyway, I guess I can play along with the charade.
It turns out software engineer guy is one of those "diagnose yourself" people in the WebMD vein and insists he has mercury poisoning. He doesn't of course, nor does he have a whole host of other diagnoses insisted upon by Foreman. The patient then posts his symptoms online and promises a $25,000 reward to anyone who can diagnose him. The internet suggests some random disease (you don't really care about its name, and I can't spell it), but that too turns out to be wrong.
By the way, throughout this whole thing, Foreman and Thirteen are dealing with Foreman's new promotion and how it changes the dynamic in their relationship. Thirteen is mad because Foreman is being bossy, and Foreman is mad because he's taking her medical critiques personally. It's a recipe for disaster.
Foreman has the magical music thing that happens when House solves a case, and rushes to the hospital to dramatically stop his earlier, incorrect course of treatment. Thirteen, however, has already figured out the same diagnosis. How? Turns out she checked some of the online diagnoses and someone had posted the correct one. Well, Foreman was pretty mad, and fired Thirteen so that they could save their relationship.
Meanwhile, House is adjusting to life at home. He tries cooking, at which he excels beautifully, but it doesn't take his mind off the leg pain long enough. Then, he goes back to his old apartment and stares meaningfully at an old bottle of Vicodin. Does he take them?
We then cut to Wilson and Cuddy being convinced that he did, since he's no longer bothered by leg pain, and making him pee into a cup. The test is negative for narcotics, so why has he made this miraculous discovery? Turns out he went online and solved his own case, which he views as a failure to remake his life. His therapist decides that maybe it's best for him to return to diagnostics, since that's the only thing that makes him feel better. Ta-da! Everything back to normal.
One final thought - the video game that the patient was designing, and that we see multiple shots of looks kind of amazing, and I really want to play it now.