The first danger night John didn't even realise what it was. He would speak to Mycroft about it at great length afterwards, but in that first instance he knew nothing of the real past of Sherlock.

When John walked in Sherlock had his hands held to his face, his fists clenched tightly around something in his shaking palm. Actually, practically all of Sherlock was shaking and though John liked to think that Sherlock was infallible, he was pretty sure he recognised the symptoms.

John sat down next to Sherlock placing a hand on the stiff shoulder.

Sherlock's head snapped up clearly shocked that John was there and that he hadn't heard his friend walk in. If John had had any doubts, they were gone now at the sight of a little corner of a plastic bag poking out of the fingers in the right hand. The detective clearly knew there was no point in denying what it was.

"I don't know what to do." The words, as shaky as the rest of Sherlock, were ones John had never thought he would hear come from his friend's mouth. Sherlock always had a complete grasp of any situation he was in, but this wasn't a person who he could read; this was a demon within himself.

John held out his hand for the powder. From a cursory glance it was probably either cocaine or heroin. Right now it didn't really matter; all that mattered was that it wasn't still in Sherlock's possession.

"I haven't," Sherlock insisted, "not in years, but my mind, it doesn't ever shut up."

John didn't need an explanation, not now. Explanations could wait for a time when Sherlock was feeling less fragile, less tempted.

He instead pulled Sherlock's head to his shoulder carding his fingers through the dark locks hushing him until he fell asleep and the shaking stopped.