Tangle of Thornes (Eva Thorne, #1)

When Eva's brother is murdered in a city of rude elves and matriarchal dwarves where humans have no rights, she is forced to investigate the crime herself. What she discovers brings her up against a powerful slave-trading cartel, dark gods, and—worst of all—her twin sister. Both her family and the elven authorities want her hushed. She has no money and no magic of her own with which to combat them, but she does have an illegally-freed slave, a senile nanny, and an ex-almost-boyfriend on her...