Jack the Ripper brought us here

Henry and Sherlock get caught in a case together and realise this isn't the first time they've met. They actually met at a very different time period in their life back in London. They both had worked a very famous case one that even stumped the great Sherlock Holmes. Jack the Ripper.

Takes place after the last episode and Jo is hardly talking to Henry as he sounds like a person she would normally lock up. but Sherlock doesn't see it this way he thinks this sexual tension and he isn't afraid to put that out there. Only to his surprise hears detective Hanson say that if he's going to comment on them he has to hurry up and kiss john.