A psychopathic killer targets San Francisco's most innocent and vulnerable. A young mother and her infant child are ruthlessly gunned down while returning to their car in the garage of a shopping mall. There are no witnesses, and Detective Lindsay Boxer is left with only one shred of evidence: a cryptic message scrawled across the windshield in blood-red lipstick. The same night, the wife of A-list actor Marcus Dowling walks in on a cat burglar who is about to steal millions of dollars worth of precious jewels. In just seconds there is an empty safe, a lifeless body, and another mystery that throws San Francisco into hysteria. Before Lindsay and her friends can piece together either case, one of the killers forces Lindsay to put her own life on the line – but is it enough to save the city?