Welcome to the morning after. “Sex kid” has made a huge mess – and just can’t stop barfing. Chaos comes to class, and in detention, the girls bond.

Bouncing back is the only option, so Otis throws a small gathering that turns rowdy, and Jackson deals with the healing. Who can handle the truth?

Otis and Eric get away from romance and retreat to the woods with Remi. But parents aren’t perfect, as Maeve knows. Later, Ola follows her heart.

Ola wants to go all the way, but Otis is on edge. Jean and Maeve need their space. Jackson has performance worries, and star-crossed lovers reconnect.

On her way to surprise Maeve, Aimee gets a horrible shock on the bus. Rahim connects with Eric as a Milburn family dinner gets seriously awkward.

After Jean makes a cringey appearance at school, Otis tries his hand at pleasing Ola – and advising a hapless teacher. Fearless Maeve buckles.

Masturbation turns out to be Otis’s secret talent, but can he master his unruly desires for Ola? A chlamydia outbreak distracts the student body.

Otis feels violated by Jean’s new book, and Maeve takes the fall for her brother. Eric serves detention with an old foe, while Lily’s body betrays her.

The big dance brings out the best, and the drama, in Moordale’s student body. Otis finds a date, Maeve gets her dress, and Eric returns with style.

Eric’s trauma isolates him, and Maeve’s essay wins a prize. Otis tries to hook up with Lily, but his deep-seated issues get in the way.

An explicit pic puts a mean girl on the spot. Maeve wants to track down the shaming culprit, forcing Otis to make a tough choice on an important day.

Eric realizes Otis has fallen for Maeve. But the young sex therapist finds himself torn when hot guy Jackson seeks help with his secret crush.

Otis’ clinic achieves liftoff, as does his attraction to Maeve, who unexpectedly asks him for help. Eric swings off on his own and fields a come-on.

Egged on by Maeve — and finding that dispensing sex tips is tougher than he thought — Otis tries offering free advice at a classmate’s house party.

Despite the ministrations of sex therapist mom Jean and encouragement from pal Eric, Otis worries that he can’t get it on. He’s not the only one.

Inexperienced Otis channels his sex therapist mom when he teams up with rebellious Maeve to set up an underground sex therapy clinic at school.

Terror reigns in the food court when the Mind Flayer comes to collect. But down below, in the dark, the future of the world is at stake.

With time running out — and an assassin close behind — Hopper’s crew races back to Hawkins, where El and the kids are preparing for war.

Dr. Alexei reveals what the Russians have been building, and Eleven sees where Billy has been. Dustin and Erica stage a daring rescue.

Strange surprises lurk inside an old farmhouse and deep beneath the Starcourt Mall. Meanwhile, the Mind Flayer is gathering strength.

A code red brings the gang back together to face a frighteningly familiar evil. Karen urges Nancy to keep digging, and Robin finds a useful map.

With El and Max looking for Billy, Will declares a day without girls. Steve and Dustin go on a stakeout, and Joyce and Hopper return to Hawkins Lab.

Nancy and Jonathan follow a lead, Steve and Robin sign on to a secret mission, and Max and Eleven go shopping. A rattled Billy has troubling visions.

Summer brings new jobs and budding romance. But the mood shifts when Dustin’s radio picks up a Russian broadcast, and Will senses something is wrong.

Eleven makes plans to finish what she started while the survivors turn up the heat on the monstrous force that’s holding Will hostage.

An unlikely hero steps forward when a deadly development puts the Hawkins Lab on lockdown, trapping Will and several others inside.

Psychic visions draw Eleven to a band of violent outcasts and an angry girl with a shadowy past.

Will’s connection to a shadowy evil grows stronger, but no one’s quite sure how to stop it. Elsewhere, Dustin and Steve forge an unlikely bond.

Nancy and Jonathan swap conspiracy theories with a new ally as Eleven searches for someone from her past. “Bob the Brain” tackles a difficult problem.

An ailing Will opens up to Joyce — with disturbing results. While Hopper digs for the truth, Eleven unearths a surprising discovery.

Dustin adopts a strange new pet, and Eleven grows increasingly impatient. A well-meaning Bob urges Will to stand up to his fears.

After Will sees something terrible on trick-or-treat night, Mike wonders whether Eleven’s still out there. Nancy wrestles with the truth about Barb.

As the town preps for Halloween, a high-scoring rival shakes things up at the arcade, and a skeptical Hopper inspects a field of rotting pumpkins.

Dr. Brenner holds Hopper and Joyce for questioning while the boys wait with Eleven in the gym. Back at Will’s, Nancy and Jonathan prepare for battle.

Eleven struggles to reach Will, while Lucas warns that “the bad men are coming.” Nancy and Jonathan show the police what Jonathan caught on camera.

A frantic Jonathan looks for Nancy in the darkness, but Steve’s looking for her, too. Hopper and Joyce uncover the truth about the lab’s experiments.

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.

Refusing to believe Will is dead, Joyce tries to connect with her son. The boys give Eleven a makeover. Nancy and Jonathan form an unlikely alliance.

An increasingly concerned Nancy looks for Barb and finds out what Jonathan’s been up to. Joyce is convinced Will is trying to talk to her.

Lucas, Mike and Dustin try to talk to the girl they found in the woods. Hopper questions an anxious Joyce about an unsettling phone call.