After proving that he was really not human- which mainly consisted of a stubborn Sherlock taking endless DNA samples and a medical checkup by a reluctant John- The Doctor and Clara were given tea by the landlady.
" We came because well..." The Doctor hesitated a bit "well you have an alien psychopath after you. Goes by the name of Jim Moriarty."
Sherlock sat up almost instantly when he heard the name, but John wasn't too keen. "James can't be an alien its not possible!" He said.
"Once you eliminate the impossible, whatever remains- no matter how improbable- is the truth," Sherlock mumbled, "but before I am willing to accept whatever help you're going to give, you've got to convince me that this isn't some big setup."
"The tests weren't good enough?!" The Doctor cried, exasperated. Sherlock mockingly shook his head.
"Well then, time you saw the TARDIS!"