A swarm of Demodogs erupts from the depths of the tunnels, shattering their way into the heart of Hawkins Lab. Inside, Mike, Joyce, Hopper, Bob, and Doctor Owens are suddenly aware of the creatures' relentless pursuit of Will. Joyce quickly sedates him to mask his scent and confuse the predators.
But disaster strikes when a catastrophic systems failure plunges the entire facility into darkness, trapping them in a secure office on the upper floors. With the Demodogs now free to roam unchecked, Bob, more skilled in technology than Hopper, bravely volunteers to venture out and restore power to the critical systems. Owens remains behind, using the security cameras as eyes to guide the others to safety.
Mike, Will, Joyce, and Hopper narrowly escape, but Bob falls victim to the relentless Demodogs. The group flees to the Byers' house, where Dustin ventures a theory that the Shadow Monster is actually a Mind Flayer. After concealing their whereabouts, they interrogate Will, who taps out a urgent message in Morse code: "CLOSE GATE."
Suddenly, the house phone rings, jolting Will back to reality. The Mind Flayer retaliates, sending a Demodog to the house. But just in time, Eleven arrives and swiftly dispatches the creature, saving them from further harm.
