Giveaway prompt: Who?

Mrs. Hudson frowned as her daytime telly was drowned out by a strange wooshing sound coming from outside her window, unlike anything anything she'd ever heard before. Rising carefully from the couch (her hip was particularly bad today), she shuffled over to the front window to see if she could spy the source of the noise. A long pause, then the noise seemed to reverse itself just as the front door swung open quickly, admitting her boys from 221B. She hadn't seen them this happy and excited since the last big serial murderer case! "Sherlock!" Mrs. Hudson exclaimed, "What have you gotten yourself into?"

"Space and time, Mrs. Hudson!" Sherlock gripped her excitedly around the shoulders as John shed his jacket, shutting the front door behind himself. "We've just been with the Doctor!"

Mrs. Hudson hadn't heard Sherlock mention any other doctor other than John, but this sounded important. "Doctor who, dear?"

Sherlock was about to try to explain, but John placed a hand on each of their shoulders. "Don't worry about it," he smiled, "just a new friend we've met. Perhaps next time he comes by you'll get to meet him too." And with that, the two troublemakers clambered upstairs, leaving Mrs. Hudson wondering if this third fellow would be needing a room as well. Perhaps she could finally find a tenant for 221C!