John Cardinal has been demoted for a hunch about a case that he wouldn’t let go. But he is brought back to the Homicide Unit when the body of missing 13-year-old Katie Pine is discovered, proving his instincts correct. As the series unfolds, back on the case, Cardinal’s search for her murderer soon becomes an all-consuming race to stay ahead of a serial killer. Meanwhile, he must manage his own precarious family issues and secrets, and keep a watchful eye on his new partner, Detective Lise Delorme, who he believes may have her own secret agenda.