New Zealand's remote Milford Track seems the perfect place for forensic investigator Alexa Glock to reconnect with her brother Charlie, with whom she hasn't spent much time since they were kids. But their backpacking trip seems ill-fated from the start: She must stop on the way to examine nine skeletons—most likely Māori tribespeople—whose graves have been unearthed by highway construction. Before she opens the first casket, a Māori elder gives her a dire warning: The viewing of bones can unleash misfortune to the living. Or worse.

Though Alexa dismisses his words as superstitious, they soon come back to haunt her as the idyllic hike takes a sinister turn. First, Charlie is aloof and resentful of the time Alexa has spent at work. Then a rock avalanche nearly carries her away as it reveals the skeletal remains of someone who has clearly been stabbed to death. When a fellow hiker goes missing and is later found dead, it’s all Alexa can do to focus on the science as she investigates two murders, while trying not to become the third victim.