A serial killer targets the detectives of the 87th Precinct, forcing the remaining officers to identify a motive before they become the next victims. Detective Steve Carella leads the investigation into the deaths of his colleagues, navigating a landscape of urban corruption and personal danger. The narrative follows a procedural framework, documenting the methodical collection of evidence and the high-stakes pressure of police work. Carella faces physical threats from the city's criminal elements while attempting to reconcile the lack of clear motives behind the targeted assassinations. The story maintains a focus on the logistical realities of law enforcement in a gritty, unnamed metropolitan setting.

Readers frequently highlight the book as a foundational entry in the police procedural genre, noting its influence on subsequent crime fiction. Discussion often centers on the clinical, no-nonsense prose style that prioritizes the mechanics of investigation over stylistic flourishes. Critics observe that the pacing remains tight, reflecting the urgency of the detectives' situation as they face an unknown assailant. The balance of character development and procedural detail provides a grounded atmosphere that defines the series' reputation. Many readers appreciate the lack of melodrama, finding the focus on the daily grind of police work to be a defining characteristic of the narrative.