 Previously on Stranger Things, a Russian base is working on a super weapon to open up the gateway between our world and the upside down, and a near the point of success. Meanwhile, Mike and Eleven's relationship is going strong, much to the disgust of Hopper. The gang Minus Dustin, who is at camp, meets up at Hawkins' brand new hotspot, Starcourt Mall, where we meet Steve's scoops-a-hoi work colleague, Robin. But we're interrupted by a city-wide blackout caused by some suspicious underground activity, which also happens to disable magnets. Dustin gets a warm welcome back at home, but the heat's really getting turned up at the swimming pool. Hopper gets some advice from Joyce about Eleven's relationship with Mike, and Joyce recommends writing a heartfelt letter, which doesn't come naturally to Hopper. Nancy and Jonathan are struggling to find their way as interns for the local newspaper, and Dustin shows the newly reunited gang his high-tech radio transmitter, which he uses to communicate with his girlfriend he met at camp, which nobody believes. Mike gets under Hopper's skin, the letter is discarded, and Mike is kicked out and threatened to leave Eleven alone. With his transmitter, Dustin accidentally tunes into a secret Russian broadcast, and hears a secret code whilst Karen backs out of a date with Billy, who finds himself otherwise occupied. Eleven tries to meet up with Mike, but too scared to confront Hopper, Mike lies to get out of it, which makes a very happy Hopper, who scores a date with Joyce. The magnets stop working again, Nancy and Jonathan take their journalistic work into their own hands, and Eleven decides to hang out with Max instead. Billy is not his normal self up to the night before, and Lucas' sister Erica stirs up trouble at Scoops Ahoy. The journalistic heroes go to see an old lady whose rats are behaving oddly. Oddly familiar. Hopper has problems following the mayor's rules, and Eleven has problems following Hopper's rules of staying out of public. Concerned about the blackouts and magnets, Joyce seeks assistance from the one and only Mr. Clark. Eleven gets a new look, and catches Mike in a lie, resulting in him getting dumped. Hopper is then stood up after Joyce is distracted by the magnets. Billy kidnaps one of his colleagues from the pool, and brings her to the steel mill, where he was previously taken. And Eleven accidentally stumbles across him whilst using her powers to spy on the boys. Will has trouble accepting that the group is growing up, and Joyce tries to explain to Hopper why she's been so distracted. Nancy's rat story gets turned down, Eleven learns of the girl Billy kidnapped, and Joyce and Hopper retrace their footsteps in the research lab from their last brush with the upside down. But someone is hot on their trail. Dustin, Steve and Robin figure out the meaning of the Russian co-words and learn of a secret meeting, and the old lady with the rats has a secret of her own. Eleven and Max investigate Billy's strange behaviour, and it turns out everything's fine, or at least it appears that way before they bring more victims to the steel mill where a familiar creature is feeding. And the kids are noticing a familiar pattern. They decide to go after Billy and lure out the creature with what Will knows it hates, heat. A plan is hatched for the secret Russian meeting, and Erica's assistance is required to fit in the air duct to get there. Hopper learns the mare is corrupt and obtains information on what is really going on, and Erica is successful in accessing the Russian meeting place. This meeting place, however, turns out to be a major operation being performed underneath Hawkins. The kids corner Billy in a sauna, and Eleven fights the monster inside of Billy. The kids escape, but the people of Hawkins aren't so lucky. Dustin and gang attempt to find a way out of this newfound base, while Joyce and Hopper try to find a way in, and kidnap the Russian scientist Dr. Alexei. But as usual, someone is right behind them. Joyce tries to get information out of Alexei without success, and they try to find their way back to town. Steve and friends find a way out of the elevator of the Russian base, and Alexei finds his way to 7-Eleven. The kids discover what Billy has been up to. And Hopper and friends enlist the help of conspiracy theorist Mari, who turns out was pretty accurate with his conspiracies. The kids go to the hospital where the old rat lady was kept to learn more, but the creature is feeding too fast. In the Russian base, the gang discovers the upside-down superweapon, and then try to escape, but Robin and Steve are captured. Eleven fights the creature in the hospital, and it retreats underground to feed. The kids plan the adults plan, and Dustin and Erica plan to rescue Robin and Steve, who are being drugged and interrogated by the Russians. Using her powers to find Billy, Eleven gets a peek inside his memories, which are now shrouded in darkness, and they lead her to the steel mill, where the creature is growing stronger by the minute. At the funfair, the town of Hawkins is celebrating, oblivious to the looming danger right on their doorstep. Dustin and Erica find Steve and Robin, who are rendered useless due to the drugs, and they finally find an exit. The creature comes for Eleven, and her leg is badly wounded. In search for the kids, the adults head to the fair, and Mari draws attention to the sexual tension between Joyce and Hopper, and finds a friend in Alexi. The kids go to a nearby store to plan how to defeat the creature. Dustin finally makes contact with the rest of the kids, whilst Robin and Steve get the drugs out of their system. Steve confesses he likes Robin, and Robin explains he's barking up the wrong tree. Meanwhile, at the fair, whilst Joyce and Hopper search for the kids, Mari shows Alexi the fun that can be had at a carnival. Hopper, Joyce and Mari narrowly manage to escape the fair. In her usual fashion, Eleven saves the day. However, the wound in her leg overcomes her, and she discovers a part of the creature is inside her, and she must remove it. The gang is then reunited, and learn the Russian superweapon needs to be shut down to close the gate between the two worlds. It's Hopper, Joyce and Mari's turn to go underground, and Dustin's transmitter is used to talk to them. Mari goes deeper inside the base to destroy the weapon from the inside out, but time is running out. Since Eleven removed the creature from her leg, her telekinetic powers are now gone, and the creature now knows where they are. Whilst waiting for Mari, Joyce and Hopper open up about their feelings towards one another. Mari tries to sabotage the superweapon, and the kids try to escape them all, but are thwarted by Billy. Well, nearly. It turns out Dustin really does have a girlfriend. Billy comes for Eleven and presents her to the creature, but the gang distracts it with fireworks. To destroy the superweapon once and for all, two people are needed. However, Hopper is delayed fighting the Russian henchmen. Eleven reminds Billy of who he really is by showing him the memories she saw. The buyer's household decides to move away, and a powerless Eleven is going with them. Mike and Eleven share a final kiss before Joyce hands over Hopper's discarded letter for her to read. Meanwhile in Russia, the Russians have prisoners being held in cells, taking them out and feeding them to an all too familiar creature.