Answer: In the series finale of House, it appears House had succumbed to a fiery end in a building blaze. His colleagues attend his funeral and issue forth their fond memories of the late doctor. As Wilson begins his tirade in spite of House’s selfishness, a cellphone makes a noise; it’s in Wilson’s pocket, and it says, “SHUT UP YOU IDIOT.” Wilson is seen driving up to see that House is sitting outside the apartment building, very much alive, having escaped the fire from the back door of the building. He swapped dental records with an already-dead person in the building fire, and now is presumed dead by all. Wilson and House later drive off on motorcycles to spend Wilson’s last five months together, doing who knows what.
