In Chapter Seven: The Bite, the seventh episode of the third season of the series, Strange things start happening around Hawkins as people start getting afflicted with the mysterious disease that is causing them to behave erratically. Meanwhile, Hopper and Joyce team up to investigate what could be causing this outbreak.
The episode begins with a group of rats acting strangely in a warehouse, followed by a worker who gets bitten by one of the rats. Quickly, he succumbs to the disease and starts behaving bizarrely.
At the same time, Dustin, Steve, Robin, and Erica continue their search for information about the Russians they overheard at the mall. The group eventually finds a secret lab hidden beneath the mall, which they believe is connected to the Russians.
Meanwhile, Hopper and Joyce meet with Mayor Kline to discuss the strange occurrences happening in Hawkins. Kline reveals that the nearby abandoned steelworks has been bought by a company called Starcourt Industries and that he has been advised to keep quiet about it.
As the episode progresses, more people in Hawkins fall ill, including Billy, who is taken to the hospital after attacking his sister Max. It is discovered that Billy was bitten by the same rat that caused the first case of the disease.
Eventually, Hopper convinces Dr. Owens to tell him what is happening. Owens reveals that the rats are being used to spread a virus that allows the mind flayer to control its hosts. The group realizes that the Russian lab is working on a remedy for the virus, but they must hurry to retrieve it.
In the end, the episode leaves us with Hopper, Joyce, and Murray making their way into the Russian lab, and Nancy and Jonathan getting trapped in the hospital with the infected Billy.
Chapter Seven: The Bite is a tense episode that builds on the mysteries and threats that have been introduced in the previous episodes. It brings the characters closer to discovering the truth about the mind flayer and introduces new challenges that they must overcome. Overall, it is a compelling installment in the ongoing story of Stranger Things.