Every summer, in an event commemorated throughout the Tohono O'odham Nation, the Queen of the Night flower blooms in the Arizona desert. But one couple's intended celebration is shattered by gunfire, leaving a little girl-the sole witness to the bloodshed-without the only family she's ever known. To her rescue come Dr. Lani Walker-who sees the trauma of her own childhood reflected in her young patient-and Dan Pardee, an Iraq war veteran and member of an unorthodox border patrol unit. Joined by Pima County homicide investigator Brian Fellows, they must protect the child while tracking down a ruthless killer. In a second case, retired homicide detective Brandon Walker is investigating the long unsolved murder of an Arizona State University coed. Now, after a 50-year silence, the one person who can shed light on that terrible incident is willing to talk. Meanwhile, Brandon's wife Diana is reliving memories of a man whose death continues to haunt her. As these crimes threaten to tear apart three separate families, the stories and traditions of the Tohono O'odham people remain just beneath the surface of the desert, providing illumination to events of both self-sacrifice and unspeakable evil.