The kids look for answers about the mutant creatures plaguing their town and get a helpful lesson from Mrs. Baxter, their substitute science teacher.

A worried Mike decides to come clean to Hopper, and Dustin drags Steve into the H.I.C. Nikki welcomes Will to the mosh pit. Lucas and Max hit the arcade.

Nikki joins the party — and the newly formed Hawkins Investigators Club. Strange things take root at a nearby farm and shake up the Winter Festival.