When a severed hand, clutching a gun, is found in a Chinatown alley in downtown Boston, detective Jane Rizzoli climbs to the adjacent roof-top and finds the hand's owner: a red-haired woman whose throat has been slashed so deeply the head is nearly severed. She is dressed all in black, and the only clues to her identity are a throwaway cell phone and a scrawled address of a long-shuttered restaurant. With its wary immigrant population, Chinatown is a closed neighbourhood of long-held secrets – and nowhere is this more obvious than when Jane meets Iris Fang. Strikingly beautiful, her long black hair streaked with grey, she is a renowned martial arts master. Yet, despite being skilled in swordplay, neither she nor her strangely aloof daughter, Willow, will admit any knowledge of the rooftop murder. And pathologist Dr Maura Isles has determined that the murder weapon was a sword crafted of ancient metal from China. It soon becomes clear that an ancient evil is stirring in Chinatown – an evil that has killed before, and will kill again – unless Jane and Iris can join forces, and defeat it…