focuses on a single case that starts with a gut punch, as a loved one recounts the last time they saw their son, daughter, brother, sister, boyfriend or girlfriend before they vanished into thin air. These are real mysteries about real people who have disappeared from families and relationships, abandoning lives, leaving only theories in their wake: Where did they go? Why? Did they run away, or were they the victims of foul play? Those left behind, heartbroken and shellshocked, struggle to solve the puzzle. Viewers are encouraged to join the search, to help the families find closure by contacting police departments and Crime Stoppers. poses a crucial question: Someone out there knows something … Is it you?