Time travel/alternate history somewhat in the 'Connecticut Yankee In King Arthur's Court' (or' Crosstime Engineer') vein. Reads like the Mission Diary it's framed as - the writing is promising journeyman work - but for a REALLY interesting mission. The main characters are pretty bloody minded - nukeing a medieval city to get rid of maybe 5% of the population would take a thicker skin than mine, for example. Heinlein's 'Time Enough For Love' is referenced, staying just this side of the homage/fanfic line. Was surprised to find this one offered for free - it's worth paying for. There is certainly worse out there from major publishers. The author might - if he hasn't already - consider submitting to Baen Books, which has published a deal of similarly themed work.