When police officer Nikki Parker's son goes missing, she joins the LAPD's Missing Person's Unit to help other people find their loved ones, even as she searches for her own. Six years later, her world is turned upside-down when her ex-husband, Devon Zoellner, shows up with a proof-of-life photo of their missing boy. Or is it? It’s a case-of-the-week show with a case-of-a-lifetime story running through it — a story that alternately brings our two main characters gut-wrenching heartache and heart-pounding joy.