While Sherlock is "dead," one of the places he ends up in is Afghanistan. Up until then he's been able to put John - and John's very real grieving - out of his mind, but somehow being in/near the place where John got shot is really getting to him. Maybe he is able to deduce the true story behind John's injury (instead of the half-truth John admits to), or maybe he solves a case involving some of John's old team, or maybe it turns out the incident in which John got shot is somehow connected to Moriarty's network? However it works out, Sherlock is painfully awRe that THIS is where John Watson's life took its first turn toward them being flatmates. And it's all he can do not to just say sod it all and come back to John.

(Can be UST Johnlock or platonic, but lots of angsty Sherlock having to deal with painful emotions, please!)