when i made my mom watch sherlock with me she was convinced by like the end of season 1 that lestrade was going to die purely on the basis that he's too good for this world and like honestly. got me thinking.
like. au where lestrade gets gravely mortally injured sometime during the events of TFP and we get to see mycroft in this pure, life or death *panic* while john and sherlock (also panicking, but quieter) are like "???" in the background and we get to find out that greg and mycroft have actually been really close offscreen this entire time but nobody knew (except moriarty/eurus, apparently) until now
bonus points if it's through a screen like the sherlock-molly scene. bonus bonus points if they never got to confess to each other and were just stuck in this "will they won't they" type of situation and then greg dies not knowing.