The police chief Jim Hopper reveals to Eleven secrets he has long waited to learn about his old life, when he was a police detective in New York City, and confronts his past before the events of the hit series Stranger Things.

Christmas, Hawkins, 1984. All police chief Jim Hopper wants is to quietly enjoy his first Christmas with Eleven, but his adopted daughter has other plans. Despite Hopper's protests, she brings up a cardboard box from the basement labeled "New York" — and the tough questions begin. Why did Hopper leave Hawkins so many years ago? What does "Vietnam" mean? And why does he never talk about New York?

Although he would rather face a horde of demogorgons than talk about his past, Hopper knows that he can no longer avoid the truth. So he begins recounting the incident in New York — his last big case before everything changed...

Summer, New York, 1977. Hopper starts over after returning home from Vietnam. His young daughter, beloved wife, and career change to a detective in the New York City Police Department ease his return to civilian life. But when invisible federal agents suddenly appear and seize his files on a series of brutal, unsolved murders, Hopper takes matters into his own hands and risks everything to uncover the truth.

Soon, Hopper finds himself on a secret mission within the notorious street gangs of New York City. However, just when he is ready to solve the case, a blackout covers the city's boroughs, plunging Hopper into a darkness deeper than he has ever faced before.