Summer, New York City, 1977. Hopper is starting over after returning home from Vietnam. A young daughter, a caring wife, and a new beat as an NYPD detective make it easy to slip back into life as a civilian. But after shadowy federal agents suddenly show up and seize the files about a series of brutal, unsolved murders, Hopper takes matters into his own hands, risking everything to discover the truth.
Soon Hopper is undercover among New York’s notorious street gangs. But just as he’s about to crack the case, a blackout rolls across the boroughs, plunging Hopper into a darkness deeper than any he’s faced before.