At Juniper Hill Asylum in 1935, a young girl named Mabel is taken by Ingrid, the asylum’s orderly, into the basement, as “a clown told her to meet him there”. The pair are distracted by a red balloon floating through the air – and out of the doorway, Pennywise the Clown appears.

In present day, Leroy, terrified after what he witnessed, is berating Will for going into the sewers and causing the incident that resulted in the death of Pauly. Will tries to argue that he was just helping his friends, but Leroy bans him from going back to Derry, knowing that he’s safe in the air force base. Will refuses, saying that he refuses to back down from the danger, emotionally blurting out that he won’t let his friends die like Leroy did. Enraged, Leroy slaps his son, knocking him to the ground, and with the entire family in shock, Will runs out, warning his father that the creature has gotten into his head.

Over in Derry, the search is on for Hank Grogan, with wanted posters plastered around the town and the residents rounding up posses to search for him. Ronnie is terrified and distracted as she meets with the group at the lookout point, while Lilly shows everyone the dagger she found that stopped the creature in the sewer.

She figures they can use it to go back down there and kill it, but Ronnie hits out at her, reminding her that they almost died. She calls Lilly crazy for suggesting they return, which enrages her, and the girls get into a furious argument. Lilly says she was just trying to help, while Ronnie says if she hadn’t gone sticking her nose into things, the boys would still be alive, and her dad would not have been arrested. Ronnie furiously tells her that she should never have been let out of Juniper Hill and storms off, with Will going after her.

Ronnie admits she may have gone too far with what she said to Lilly, but she was scared and tired. The pair share a hug and almost kiss, but are interrupted by Charlotte, who’s tracked him down. Charlotte demands both Will and Ronnie get into the car, and she drives them back to the base.

At the soldier’s clubhouse – now christened as “The Black Spot” - Hallorann is out of sorts, still shaken from what he experienced in the sewers. He goes to lie down in the back room, but two of his officers stop him, saying they need to talk. They reveal that Charlotte has snuck Hank into the base, and they’ve been hiding him there. Hallorann is enraged and wants to be kept out of it. Hank promises not to leave the room he’s in. He then has a tearful reunion with his daughter as Charlotte arrives with her and Will.

That night, at the lookout point, Marge is seen tending to her bad eye, and gets a fright when Rich appears behind her. Instead of being scared, he offers to help her redress her wound. The pair share a sweet moment together, with him calling her eye wound ‘the coolest thing he’s ever seen’. He later throws a glider off the lookout, which makes its way into a sewer grate.

Hallorann is struggling with whatever he was forced to open in his mind and has taken to drinking in the dark in his room on base. Leroy comes to check up on him and inform him Shaw is continuing his mission to find the pillars. Hallorann says they should’ve left the being alone, as he sees dead soldiers in the window.

Hallorann shares that, when he was younger, he was taught by his grandmother to hide things he didn’t want to see anymore in a box inside his head. Now it’s open, it’s been spilling out into his head in full force. He can now see the dead walking among them and is hearing voices that refuse to stop in his head, telling him things the living are not meant to know.

Leroy sympathises but encourages him to complete the mission assigned to them and put it back away like before. He says it’s “what’s right” which enrages Hallorann, who tells him to get out. Leroy leaves, but before he does warns Hallorann he needs to do his sworn duty or leave in handcuffs.

When he gets home, Charlotte is packing a suitcase, preparing to leave after his earlier outburst. Leroy apologises and says he’s been messed up after what he witnessed in the sewer and what happened to Pauly. He insists he just wants to protect his family and the country, but Charlotte is furious he moved the family here in the first place. She also shares Hank’s location and tells him she plans to move with Will back to Shreveport and away from the madness he’s dragged them into.

At school, Lilly is struggling to concentrate after her encounter with Pennywise in the sewers, still clinging on to the dagger to feel safe. She envisions a twisted form of her dead father emerging from her desk, and screams at it to stay away, but gets in trouble with the teacher. At her wits’ end, she storms out of class.

Rich and Marge share the news about Ronnie’s dad, having been told by Will. Rich notes they’ve been sworn to secrecy. He then gifts her an eyepatch he found in his attic, with the pair sharing another cute moment until the Pattycakes come up to her, demanding she join them instead of “sitting with the freaks”. Marge declares she is one of the freaks, showing off her battered eye to scare them, and prompting one of them to be sick. Rich looks on adoringly as she sits back down, beaming.

That evening, Will takes Rich and Marge to the airmen’s clubhouse to visit Ronnie and Hank. Lilly, now alone, heads to Ingrid’s house to talk but finds the door open with no one home. Sneaking in, she follows music to the attic and looks through a photo album – several of which show Ingrid’s father, who bears a resemblance to Pennywise.

When Ingrid turns up, she asks why she’s there, and Lilly bursts into tears as she shares that she found Matty in the tunnels. But as she holds her, Lilly spots a photo of her dad dressed as Pennywise in the corner of the room. Ingrid realises she’s “seen him” and bursts with joy, saying she “did it” and brought him back. She reveals that she followed the group in the cemetery, dressed in her own clown costume for a chance of seeing him again.

Shocked, Lilly asks why she did it, and Ingrid shares that her dad once performed as Pennywise the Dancing Clown at the local circus, before he was “taken from her”. She stayed in Derry in case he came back, taking a job at Juniper Hill when the carnival moved on. It was there she overheard Mabel mention the clown in the basement back in 1935.

Ingrid took Marge down to the cellar, where Pennywise trapped her and devoured her, leaving Ingrid horrified and helpless behind a door. Once he’d finished, he played the music she remembered as a child, and for a brief moment she saw her father again through the door window. He told her he missed her and encouraged her to open the door and let him in, which she does.

While she admits he was “different”, she says she finally felt whole again for the first time since his disappearance and has been feeding him children so she could see him. She believes if he sees her dressed as Perriwinkle, her clown, he could break free.

Ingrid promises she would “never let anything hurt Lilly” but can’t say the same about her friends. Ingrid says she should understand having lost her own father - wouldn’t she do the same thing? Lilly says her father is dead and not coming back, but Ingrid says that no one ever really dies in Derry.

Using the dagger, she cuts Ingrid’s hand and escapes on her bike with a bloody handprint on her dress.

At the army base, Ronnie refuses to leave now that she’s back with her dad, despite Lilly needing her help. Will goes after her to try and talk her round alongside her father, but he refuses to let her go. Instead, Hank tries to get to know more about Will, realising he’s sweet on Ronnie. He tells him that should something happen to him, it’s good to know that Ronnie has good friends to look out for her.

At the bar in town, a mob of local men are discussing their failed efforts to locate Hank, when the Chief walks in. He says he knows where Hank is being hidden after a tip off from an anonymous woman. However, he has been fired from his position and officially can’t give him so much as a traffic ticket. But the clear implication is that they are going to form a lynch mob.

As the party continues at The Black Spot, Hallorann arrives to continue drinking, while Marge and Rich enjoy the music and dancing. They order a coke, but the barman slips them something stronger in it – calling it “Airforce Coke”. When Will returns, he tells them he’s not had any luck.

With drinks flowing and the band’s drummer passed out drunk, Richie surprises everyone by showing his talent on the drums as he takes to the stage. With good moods all around, the kids let their hair down and enjoy themselves – with Marge’s crush on Rich only growing. Across town, Ingrid dresses up in her clown costume in preparation to see her father, and the lynch mob arrives at The Black Spot, masked and heavily armed.