Secret-Keepers

"You're...you're him."
"No, sorry. You must be confusing me with someone else."
"No, I'm not. You're defidently him. How...how are you alive? You jumped off a bloody roof!"
"It's something only I will ever know."
"Why haven't you returned?"
"I've got reasons you can't possibly understand."

In which an ordinary woman discovers the secret of Sherlock Holmes' death: that it had been fake all along.