This is a complicated and intriguing sci-fi novel, with a lot of original elements I haven't encountered before. Cheris is a military Captain in the Kel, one of six branches of an interplanetary ruling government. This government draws its power from its citizen's observance of a ritual calendar- their days of fasting, meditation and celebration all rigidly controlled. The power of these beliefs feeds exotic weapons, which the Hexarch uses to subdue heretics (people who follow alternate calendars). When a key fortress falls under heretic control, Cheris is put on a short list of potential commanders to win it back. She asks for one weapon: the revived ghost of the most infamous general of the empire, Shuos Jedao. Jedao won every single battle he ever fought... until he went mad and killed over a million people. When Cheris is chosen, this undead tactician is implanted directly into her brain, and the two of them have to come to enough of an understanding to win the war- or Cheris is in danger of going insane as well. Cheris is queer, though her sexuality doesn't play much of a role in this book. My solo complaint is that some of the operations of the calendar and the exotic weapons are slightly too complicated to easily follow, but the book moves at a fast pace and I am extremely interested to see where the story in the sequel goes after the tense, semi-cliff hanger ending.