"As you can probably imagine, it destroyed him. Sherlock has never been one for letting people in, letting people close. He fell in love with Irene, and then she was murdered to punish him for getting too close to M. All this happened in London. He couldn't stand to be there anymore, so he fled to New York. I met him a few months later."

She takes a breath.

"At the end of my time working with him as his sober companion, there was a murder in New York. The murderer left behind a pool of blood."