Exactly how steamy is this story?
PG
There's precious little sex in The Killer Angels. Actually, there aren't any female characters to speak of.
There is this: Joshua Chamberlain has a sexy dream with his wife in it at one point, but it's not actually described in any detail. The Killer Angels definitely leans more towards violence than towards sexuality, overall, which could earn it a rating anywhere from a PG to an R, depending on how graphic you want the bloodshed to be.