Summoned by Lucas Davenport to investigate a pair of murders in which the victims are found with lemons in their mouths, Minnesota Bureau of Criminal Apprehension investigator Virgil Flowers struggles to find a connection that could prevent additional killings.

"When Detective Macy Greeley is called to Wilmington Creek, a sleepy ranching community in northern Montana, she expects an open-and-shut, if high-profile, murder case. What greets her is anything but. John Dalton, a soldier returned home from serving in Afghanistan, has been shot dead in an alleyway outside a local bar. Macy can't see any obvious motive for the attack, but John's closest friends and his twin sister Jessie have been keeping secrets....