CIU revisits the case of Sierra Macy, a teenage girl who was kidnapped ten years ago and assumed dead - until she manages to escape her captor's home after he suffers a heart attack and dies. Sam, one of the original prosecutors, steadfastly believes that the right man was convicted: Sierra's former teacher Josh Fleck. Sam's undeniable conflict of interest has Hayes second-guessing her decision to keep him on the CIU review of the case. Meanwhile, Hayes is determined to intercede on Wallace's behalf - and against his wishes - in an investigation into his professional misconduct. Her stunning discoveries about quid pro quos that Wallace brokered in her cocaine bust and an earlier case they worked back in Chicago force the two to re-examine their personal and professional relationships.