Constance Greene confronts Manhattan's most dangerous serial killer, Enoch Leng, bartering for her sister's life, but she is betrayed and turned away empty-handed, incandescent with rage. As Pendergast focuses on saving the unstable Constance in her fanatical quest for vengeance, she strikes out on her own: to rescue her beloved siblings from a tragic fate and take savage retribution on Leng. But Leng is one step ahead and has a surprise for them all.