A body is found brutally murdered in San Francisco's Golden Gate Park. Homicide detective Lindsay Boxer knows her way around a crime scene. But nothing can prepare her for the shock of recognition: the victim is Warren Jacobi, Lindsay's former partner who rose to chief of police. A top detective until the end, Jacobi managed to leave Lindsay a clue. Following a trail of evidence along the west coast, the Women's Murder Club pledges to avenge Jacobi's death before the killer can take another one of their own.