Sixty years after the Eagle of the Ninth, Cottia still lives on the farm in the Downs that she, Marcus and Esca set up together. Britain is in confusion after four years of civil war across the Empire. The great house of Placidus backed the wrong imperial claimant, and now young Servius Placidus, the last of a long line, is on the run from the newly-established Emperor Severus's revenge. Then one of Severus's men is found dead....
Read on Ao3 It's 18618 words. Nobody has sex.
Now with some lovely art by emisolde!
ETA actually, none of the featured characters have sex, but there is an ongoing joke about the sexual prowess of one Biccus. I wonder if that is enough to make it not count as 'gen' ? I don't really know how these things work tbh.
In a way I wish I'd made this longer, because I had so much potential backstory for Centurion Crispus that didn't make it into the tale. But on the other hand, writing whodunnits turns out to be really hard. You murder someone and then you have to figure out how and why! It's so much easier to read them and have the detective and author do the hard work for you. :-D