There was a little zing of satisfaction in Mycroft that he had found out first, but his voice didn't convey any change at all.

"Ah, I see." He said, simply. "I appreciate you taking care of Sherlock. He's never been one for surprised. It came as quite a shock to him when he died. I had to watch over him for near a week before he finally started to come to terms with being a Vampire."