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 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.