The third episode of the third season of Stranger Things, Chapter Three: The Case of the Missing Lifeguard, starts off with the disappearance of Billy and Heather, a lifeguard at the local pool. The team is starting to piece things together regarding the strange happenings in Hawkins as the plot thickens.

Mike, Lucas, and Dustin are still trying to decode the Russian message they intercepted and discuss their theories. Meanwhile, Hopper and Joyce question a number of townspeople about the strange goings-on in Hawkins, but they hit several dead ends.

Max and Eleven are still worried about Billy, and Eleven uses her powers to spy on him. They discover that he is being controlled by the Mind Flayer and that Heather is also under his influence. Billy tries to get Eleven under the Mind Flayer’s control too, but she resists and both Billy and Heather escape.

Joyce enlists the help of a former colleague, Alexi, to try and decode the Russian transmission that the team intercepted. After a lot of effort, Alexi manages to translate it, revealing that the Russians are trying to open a gate to the Upside Down in Hawkins. This leads Joyce to conclude that the strange electromagnetic activity is a sign that the gate is already open.

Meanwhile, Nancy and Jonathan are continuing their investigation into the strange disease affecting the townspeople. Their investigation leads them to the local hospital, where they see the aggressive and explosive behavior of an infected woman. They also discover that the Hawkins Post has been bought out by a large corporation and they suspect a conspiracy cover-up.

The episode ends with Eleven and Max trying to find the Mind Flayer’s lair. They follow the clues to the abandoned steelworks where they discover a host of flayed rats, and then witness Billy and Heather dragging a new victim into the steelworks. The scene is set for a high-tension confrontation between the Mind Flayer, Billy, and Eleven in the upcoming episodes.