When a "TBBT" old classmate and neighbor appeared in Sherlock's world.
Sherlock Holmes: Well, I have a friend named Yvonne farrch Cooper, and she is female. But she is not my girlfriend.
John Watson: There is no reason why I am convinced that neither Sherlock nor Yvonne can be left alone in a crowd...
Mycroft Holmes: If Yvonne wouldn't compete with me for sweets, I'd be happy to play chess with her.
Mrs. Hudson: Yvonne is a good girl, although sometimes her behavior is even more incomprehensible than Sherlock's.
Jasmine Hope: Dr. Cooper is great.
Greg Lestrade: Sometimes, we need Dr. Yvonne.
Sally Donovan: Freak.