So, here's a thing. Epistolary. WWII AU. Conversations that include a lot of "gosh" and "swell". Does that tick any of your boxes? Then here you go...
Fandom: Criminal Minds
Rating: NC-17 (eventually)
Characters: Emily Prentiss/ Spencer Reid, Aaron Hotchner, original characters
Warnings: sexual content, war-related violence, f/m relationship, canon divergence, AU
Length: currently 14k (WIP) - chapter 1 of 3 posted
Summary: In 1942 at the height of WWII, Emily Prentiss receives news of her brother's death in occupied France. As she attempts to uncover details about his passing, she begins corresponding with the young lieutenant responsible for his death. Those letters will change the course of her life.
Read it
on Ao3