John had always tried to guess Sherlock's upbringing in an effort to understand his strange lover, so when he finally met Sherlock's parents, it was a shock how normal, friendly and...warm they are, in comparison to their sons. So why did Mycroft and Sherlock turn out that way, since they were brought up in a relaxed and loving environment.

The question keeps racing round John's brain, and against his better judgement John starts secretly delving into Sherlock's past. But like everything with Sherlock, nothing is straightforward or can be taken at face value, because as Sherlock himself states: Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth.

John is about to discover how true that is.

JohnLock would be awesome and adored. Mycroft/Lestrade is also welcome if desired. Hurt!Sherlock would also be perfect