Summer brings new jobs and romance; while attempting to contact Suzie, Dustin picks up a Russian broadcast on his radio; Will senses that something is wrong.
Nancy and Jonathan investigate a lead; Steve and Robin volunteer for a secret mission; Max takes Eleven shopping; Billy has disturbing visions.
El and Max search for Billy; Will insists on a day without girls; Steve and Dustin look for Russian spies; Joyce and Hopper go back to Hawkins Lab to see if there is any activity.
A code red brings the gang back together; Karen urges Nancy to keep digging; Robin finds blueprints of the mall.
Strange things lurk inside an old farmhouse; something is hidden deep beneath the Starcourt Mall; the Mind Flayer is gathering strength.
Dr. Alexei reveals what the Russians have been doing; Eleven uses her ability to see where Billy has been; Dustin and Erica plan a daring rescue.
With an assassin close behind, Hopper's crew races back to Hawkins; El and the others prepare for war against the Mind Flayer.
Terror breaks out in the food court when the Mind Flayer comes to collect El; deep beneath the mall, the future of the world is at stake.