A Vein of Friendship (смешанная)

Young Sherlock will do anything to block out the memories - hide out on the streets, self harm, drugs - but they still come bubbling to the surface. One night, a police officer comes across him (Lestrade) and offers to take him home. Unsure of the officers motives, Sherlock agrees. Has he made a mistake or is Lestrade finally someone who he can truly trust?
Story is set when Sherlock is 17 and after a traumatic experience involving a villain from canon and contains graphic elements and difficult subject matter.
[Fill for the Prompt: The general consensus in the fandom is that Lestrade met Sherlock when he was a drug addict, then took him home and helped him get clean. Yes? Yes.
But see, Sherlock knows that there’s only one reason an older man would take Sherlock to his house and show him this sort of kindness. Lestrade only wants him around for the same reasons as every other older man who ever ‘wanted him around’. He realizes he’s in no position to turn Lestrade down -- he needs the security, and has nowhere else to go at the moment -- so Sherlock preps himself and slips into Lestrade’s bed.]