Responding to a call about a suspicious duffle bag at the Chicago Lakefront, Voight is horrified to discover that the bag contains the frigid and unmoving body of a newborn baby. Determined to find the culprit who abandoned the infant, Intelligence receives a promising lead based on information provided by Chicago Med and Ruzek helps zero in on a potential suspect. Meanwhile, Voight is surprised to hear that his son is in town and Burgess and Roman grow closer.