"You said I should tell you. You said 'If you were anywhere near this kind of thing again, you could have called, you could have talked to me.'"
He looks up at John from his vantage point on the floor.
John is still stunned. He had honestly thought the worst was over. Mary, due any day now, overdue, actually, is safe. Magnussen is dead. John still wasn't entirely sure why Sherlock had pushed so hard to have the two of them reconcile, but it was clearly something Sherlock wanted too, and John had given it a good deal of thought before asking Mary back at Christmas. Sherlock was working again, proving himself more valuable by far working for M16 than in a cell somewhere. He would avoid any prosecution. John was right on the verge of a happy-ever-after. His best friend, his wife, his daughter, all a part of his life. Why now? He'd have to think about that another time. Right now, his best friend was telling him he needed him. Another danger night. And this time he was asking for his help.
"I've seen more than my fair share of addictions, Sherlock. Addictions don't really end, do they? They are like a virus. They just go dormant, they sleep. Sometimes it's really easy to wake them up."
"I need you to... stay with me. I need your help."
"We need to empty out the flat. Where is it?"
"John, Lestrade sent Anderson and a narcotics team over yesterday, you know that."
"I know they wouldn't have found a thing. Where are you hiding it?"
Sherlock trembled slightly. He looked terrified. "I need you to stay with me, John. To make sure I don't... "
"I'll stay with you Sherlock. Until this passes. But I know there's some here somewhere. It's all right. I'll watch you get rid of it. Then, if you ever feel the need for more, it will take a bit of time to get it - long enough for you to call me. And I will be right here to help you through."
"But Mary, and the baby... you can't."
"I will. My vow to you, Sherlock. I will be here for you."
Sherlock looks at him. Sees it is the God's honest truth. He smiles. John reaches out and puts his hand on his shoulder. Sherlock pulls him into an embrace.
"Here." Sherlock crosses to the test tubes and flasks cluttering the kitchen table. "Poe's 'The Purloined Letter'. Dupin was showy and superficial, but, he knew that the trick to hiding something well was to keep it in plain sight." He removes an aqueous solutionfrom the rack, places it in John's hands, then abruptly turns away.
John stares at it for a moment; he can't help but think of all the times he had searched the flat, a team of trained investigators, and there it has been all along. In an innocuous test tube.
"Sherlock, I think you should be the one to get rid of it." Sherlock nods slowly, and gestures for John to come with him to the loo.
John sees the evidence. Sees the tube dumped out, sees Sherlock drop his head down, no turning back, as they watch it swirl away.
"A moment, John".
"Of course."
John turns to leave as Sherlock gently closes the lid and sits, resting his head on the back of the bowl, looking a bit dazed. The door clicks shut, and Sherlock hears John's footsteps recede.
Sherlock smiles. With a new baby, John won't be running around with him on cases anymore, but now he knows Sherlock needs him. No longer the damsel in distress, John is once again the proper hero.
Until he can earn the respect of the Chief Superintendent, Lestrade gets the credit for the cases; John gets to be the noble husband, proud father, heroic friend; and for him, there's still always this... he stretches his long white hands around either side of the reservoir tank and lifts the lid. Of course, there is nothing inside the tank, they would think to check there. He flips the lid over and retrieves a small baggie taped to the underside, removes it, replaces the lid. He carefully pours the powder back into the test tube, slips it into his dressing gown pocket and heads back to the kitchen.
He will add some red dye to the solution this time before replacing the tube.