Carmilla, Queen of the Night, is a shape-shifting raven whose fictional exploits thrill girls all over the world. When tweens in Chicago’s Carmilla Club hold an initiation ritual in an abandoned cemetery, they stumble on an actual corpse, a man stabbed through the heart in a vampire-style slaying. The girls include daughters of some of Chicago’s most powerful families: the grandfather of one, Chaim Salanter, is among the world’s wealthiest men; the mother of another, Sophy Durango, is running for the United States Senate. For V. I. Warshawski, the questions multiply faster than the answers.