Freddy Heflin, the sheriff of a small town in New Jersey, idolizes the New York City police officers who reside there. This town, Garrison, is a suburban enclave largely inhabited by NYPD officers living outside the jurisdiction of internal affairs. Freddy, who lost hearing in one ear during a heroic rescue attempt in his youth, works a quiet sheriff's job that keeps him on the periphery of real law enforcement action. However, when a young cop named Murray Babitch is involved in a controversial shooting and subsequent cover-up orchestrated by his superiors, it shakes the foundations of this seemingly idyllic community.

As Freddy delves deeper into the tangled web of corruption, he faces resistance from powerful figures, including Lieutenant Ray Donlan, who maintains a stranglehold on the town's police officers. Freddy discovers that the officers he once admired are complicit in nefarious activities, making his quest for justice all the more perilous. Confronted with moral and physical dangers, Freddy must decide whether to uphold the law regardless of personal cost or remain a silent observer in a town where the thin blue line has entirely blurred.