For every case Temperance Brennan has solved, there remain innumerable unidentified bodies in her lab. Information on some of these is available online, where amateur sleuths sometimes take a stab at solving cases. One day, Tempe gets a call from Hazel “Lucky” Strike, a web sleuth who believes she’s successfully connected a body in Tempe’s lab to a missing persons report on an eighteen-year-old named Cora Teague. Since the bones in her lab do seem to match Cora’s medical records, Tempe looks into the case, returning to the spot where the bones were originally found. What seems at first to be an isolated tragedy takes on a more sinister cast as Tempe uncovers two more sets of bones nearby. When she then learns that the area is known as a viewing point for a famous unexplained light phenomenon with significance for a local cult, Tempe’s suspicious turn to murder by ritual sacrifice—a theory thrown into question when Hazel herself turns up dead. Still reeling from her mother’s diagnosis and the shock of Andrew Ryan’s potentially life-change proposal, Tempe races to solve the murders before the body count climbs further.