Sara Marshall, the daughter of a proud, three-generation line of Philadelphia cops, has committed the unpardonable sin. While trying to save the life of another cop, she has shot and killed a young black girl. This event has intensified an already volatile face-off between the Philadelphia Police Department and the city's large black population. As a result of this unfortunate accident, Sara's career crashes, as does here love life, and her relationship with her own family.
Before her dismissal--euphemistically called an "administrative leave of absence"--from the Philadelphia PD, Sara was investigating several murders that she was convinced were all committed by the same individual. The MO of the killer in each case was identical and yet the victims--a high school band director, a notorious pimp, and a blue collar spouse abuser--appeared to have absolutely no connection with each other.
A fourth murder occurs. This time it is Father Mark Donnelly, rector of St. Michael the Angel Catholic Church. The fifth victim is Pastor Bob Messier, Director of Christian Education at the Grace Methodist Church. All five victims are men. Each has been executed with a single bullet to the back of the head. Each has a Bible quote pinned to his body.
When the media and social networks discover the notes were all written with lipstick, they are immediately convinced the killer is a woman, and quickly label her the Madonna Vigilante.
Despite her ostracism by the PD, Sara Marshall is drawn back into these cases by her ex-partner, Kevin Stiles, whose police work has been curtailed by his own personal struggles and by his wife's critical illness.
Sara's unofficial investigation brings her into contact with several suspects, all of whom have a special affinity to handguns. Each also has an underlying dislike of men. The question becomes: can that dislike turn into hatred? And can that hatred lead to murder?
In other words, who is the Madonna Vigilante? And why is she--or he--killing people?
The final answer and the final confrontation takes place on a major city thoroughfare whose official name is the Schuylkill Expressway. To Philadelphians, the highway is not-so-affectionately called the Sure-kill Speedway. And the final high speed, heart stopping gun battle between Sara and the killer illustrates the accuracy of the highway's nickname.