Sherlock didn't want to take his eyes off of this soldier.. this.. John. He inwardly cursed Lestrade that this damn case was getting in the way of the biggest mystery for him in 300 years.

"A demon circle, a poorly drawn one." He said in a terse, clipped tone. He walked around the circle, talking as he went. "It's accurately drawn, but they botched one symbol. Lucky for you, Lestrade. If they'd gotten it right, they could have actually pulled a demon through."

"But it's wrong on purpose." He looked over to John, and then to Lestrade, looking at them as it should have been perfectly obvious.