Detectives Benson and Amaro investigate the disappearance of a teenaged girl after her young brother calls 9-1-1. While Fin and Rollins look into a possible abduction, they discover the girl had been searching for her biological father, an anonymous sperm donor. The investigation takes a startling turn when a suspect is found to be targeting several young, vulnerable women, all with the same personal connection. But the suspect isn't what he seems, and Dr. Huang must delve into his past to save the women.