Sergeant Lindsay Boxer's friend and former partner is brutally murdered in San Francisco's Golden Gate Park.

SFPD 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 onetime partner who rose to chief of police.

A top investigator 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.