In 1980s Indiana, a group of young friends witness supernatural forces and secret government exploits. As they search for answers, the children unravel a series of extraordinary mysteries.
A code red brings the gang back together to face a frighteningly familiar evil. Karen urges Nancy to keep digging, and Robin finds a useful map.
Nancy and Jonathan swap conspiracy theories with a new ally as Eleven searches for someone from her past. “Bob the Brain” tackles a difficult problem.
Dr. Alexei reveals what the Russians have been building, and Eleven sees where Billy has been. Dustin and Erica stage a daring rescue.
Strange surprises lurk inside an old farmhouse and deep beneath the Starcourt Mall. Meanwhile, the Mind Flayer is gathering strength.
An increasingly concerned Nancy looks for Barb and finds out what Jonathan's been up to. Joyce is convinced Will is trying to talk to her.
Dustin adopts a strange new pet, and Eleven grows increasingly impatient. A well-meaning Bob urges Will to stand up to his fears.
An ailing Will opens up to Joyce - with disturbing results. While Hopper digs for the truth, Eleven unearths a surprising discovery.
With El and Max looking for Billy, Will declares a day without girls. Steve and Dustin go on a stakeout, and Joyce and Hopper return to Hawkins Lab.