Nobody's Child — Libby Fischer Hellmann

A bloodstained note left for PI Georgia Davis reveals the shocking existence of a half-sister she never knew about. Her sister, Savannah, is pregnant and begging for Georgia's help. Determined to track her down, Georgia finds herself heading deep into the secretive and dangerous underworld of Chicago's illegal sex trafficking business. She soon discovers that trafficking is just a small part of the horrifying and deadly situation in which her new sister is caught up. Even worse, as Georgia tries to extricate Savannah, she comes up against an old enemy determined to make sure neither woman will escape alive. In the fourth Georgia Davis novel, Georgia faces her toughest challenge yet -- and one she might not survive.