Sherlock sat up sharply as the brilliant flash of light nearly blinded him.

And when Sherlock said that something nearly blinded him, he meant that he could nearly feel his cornea being stripped away by the sheer whiteness of the blast before him.

Sam and Dean were exposed to the light of this angel all the time – how were they still alive?

Suddenly, Sherlock remembered. There was a reason for this blast of light. There was a horrifying, heart stopping, gut wrenching reason for this blast of light. A reason that Sherlock, who faced facts and murders and evils every day without flinching, didn't want to acknowledge.

There was a horrible scream full of so much pain that Sherlock was shocked off the ground. Dean Winchester was running, sprinting, his brother less than two paces behind him, shouting, "NO, NO, NO, CAS, NO! NOOOO!"

So. It was true.

Sherlock swung around to stare at the Winchesters' target, noting with horror the crumpled trench coat, the limp body of the small man sprawled on the ground, the circle of ash surrounding him. Sam nearly crashed into Sherlock in his rush to reach Cas, and Sherlock saw that Sam Winchester, who was a hero, who was one of the strongest people that he knew, was crying.

Oh, God, Sherlock thought, beginning to walk. Oh, God, please no.

Dean was still yelling, trying to reach Cas. The Doctor was holding him back, spouting some gibberish about how the body was still radioactive, that Dean couldn't touch him yet, that it could kill him, too. "SHUT THE FUCK UP," Dean shouted, twisting and turning out of the Doctor's grip. "IT'S NOT 'THE BODY'. DON'T YOU DARE TALK ABOUT HIM LIKE THAT. IT'S CAS."

Sam ran up behind Dean, said, "Oh my God," and froze. Dean had knelt down and was trying to reach Cas, to see if he was alive, without the Doctor noticing. Sam placed his hand gently on Dean's shoulder and said quietly, "Dean."

Dean stopped.

Sherlock noticed that John was at the scene, begging the Doctor to test and see if Cas was still radioactive, so that he could check his vitals. Eventually, he was let in the circle and five minutes later, he looked up hopelessly. "I'm sorry," he said to Dean, and Sam's grip on his brother's shoulder tightened perceptibly.

Dean stood. He shoved off his brother's grip, looked right at Cas, and said, "You son of a bitch. You stupid, stupid son of a bitch."

"Dean –"

"Fuck off," Dean snapped, and wove through the battlefield to the Impala. The Doctor tried to follow him, but Sam held him back.

"Don't," he said warningly. "He needs time."

Time. Time was the one thing that they didn't have, Sherlock thought. Even with a Time Lord on their side, time was a hard thing to come by.

Castiel, angel of the Lord, had sacrificed himself to buy them some time. They'd be fucking with his memory not to use it. "We have to go," Sherlock announced, patting Sam on the shoulder. "Grab Cas and get to the TARDIS. We have work to do."