Season one takes place entirely over the course of a single week in November 1983. Sunday, Nov. 6, sets it all in motion. On that day, Eleven is forced to make contact with the monster but accidentally opens a gate to the Upside Down in Hawkins Lab. In the chaos, she escapes. However, the monster escapes too, kidnapping Will Byers that night and Barb Holland two days later. Will's mother, Joyce, begins noticing flashing lights and music that seem to be Will trying to communicate.
Eleven is found by Mike Wheeler, one of Will's friends, and he hides her in his basement to keep her safe. Mike, along with his friends Lucas and Dustin, theorise that Will is still alive and recruit a frightened El to help them. They're horrified when a body is found that appears to be Will — but, as Jim Hopper discovers, it's a decoy. El reassures Mike that Will is alive and is briefly able to contact him, and Joyce glimpses Will through the mysterious breach in their house's wall.