Stranger Things Episode 1.05 Chapter Five: The Flea and the Acrobat

Hopper breaks into the lab while Nancy and Jonathan confront the force that took Will. The boys ask Mr. Clarke how to travel to another dimension.

Will's father Lonnie assures Joyce that her experiences are hallucinations. She discovers he plans to sue the quarry where Will's body was found and demands he leave. The boys conclude that Will is trapped in an alternative dimension of death and decay, which El calls the Upside-Down. After Will's funeral, the boys ask Mr. Clarke about dimensions; quoting the many-worlds interpretation of Hugh Everett III, he tells them that a space-time tear could create a passage between dimensions.

Dustin notices that his compass no longer points north; positing that an interdimensional passage would disrupt the electromagnetic field, throwing off compasses, the boys following the compasses to find the source of the disruption. El remembers being placed in a sensory-deprivation tank to telekinetically intercept information from a Russian spy; while listening to the spy, she comes across the creature. Scared of finding the gate, El directs the compasses away from the laboratory. When Lucas notices the distortion, he confronts her. Mike defends her and he and Lucas fight. El telekinetically flings Lucas off Mike, knocking Lucas unconscious. He recovers and runs away.

Nancy and Jonathan decide to search for the creature in the woods and find a wounded deer, which the creature drags away. Following the blood trail, Nancy crawls a passage in a tree to the other world and discovers the creature feasting upon the deer. The creature gives chase. Hearing her screams, Jonathan looks for her as the passage closes.