Honor Gillette discovers Lee Coburn, the man responsible for killing seven men the night before, lying in her front yard and is forced to comply with the armed stranger, who tells Honor that she and her daughter, Emily, are in danger due to something of great value that her late husband, a police officer, has hidden.

A series of shootings exposes San Francisco to a methodical yet unpredictable killer, and a reluctant woman decides to put her trust in Sergeant Lindsay Boxer. The confidential informant's tip leads Lindsay to disturbing conclusions, including that something has gone horribly wrong inside the police department itself. The hunt for the killer lures Lindsay out of her jurisdiction, and gets inside Lindsay in dangerous ways. She suffers unsettling medical...