6.

El sits crossed legged by the side of Steve's pool. It's much bigger than any bath or tank or pizza dough freezer that she's used before, but Dustin had said it was the only option they had. Because of its size, as well as the salt, Mike had given her something called armbands that Holly uses to help her not drown.

He and Lucas had taken two each and she'd watched in surprise as they'd held them to their mouths and breathed into them and the armbands had inflated in size. Mike had smiled at her amazement and told her he was going to get her a balloon next. Even though she didn't really know what he was talking about, it felt good, because it felt like when they were younger and they'd bonded over him sharing his knowledge about the world with her.

But that good feeling hadn't lasted. Now, as he helps her put an armband on each wrist and ankle, she tries to bring it back. But her chest feels like there is a bird flapping their wings inside of it, not a heart like they said in Biology lessons, and even Mike can't make her feel better.

Talking to Will doesn't make her feel better either, but it reminds her that she needs to be brave. Courageous. He's nervous too. He doesn't say it, but she can tell from the way his hand is shaking as he hands her the funny glasses, goggles, he tells her, that he'd wrapped in layers of black tape.

She climbs down the ladder, one foot at a time, holding onto the rugs as tight as she can. The cool of the water laps at her legs. She doesn't like it one bit. She stands there for a moment, shivering in just Mike's t-shirt and Nancy's old shorts, and then pulls down the goggles over her eyes and lays back in the water.

The salt and the armbands do their job and she floats, ears submerged under the water, daylight no longer reaching her eyes. She thinks of Will, of the small boy she'd found in the Upside Down, of the brother who told her the mouthbreathers at school didn't matter. and waits to be sucked into his mind.

Nothing happens. Frowning, she rebalances herself in the water and tries again. She thinks of his smile when he wins a game, his hand over hers while he guides her paintbrush and his screams late at night when the nightmares come. There's a moment when she sees a flash of something, so brief that she cannot tell what it is, but that's as close as she gets.

She flaps around in the water and eventually makes it back into a standing position, pulling the goggles from her eyes as she does so. "You're blocking me," she says to Will.

His shoulders slump. "I am? I didn't mean to, sorry."

"We can try again," she reassures him.

"No, wait." Dustin has one finger pointed towards her. "Whenever you've piggybacked before, the other person's not known about it, is that right?"

"Yes."

"I can't un-know it!" Will says.

"No, but perhaps we can come at you unaware," Dustin says. "Like, in your sleep."

Lucas shakes his head. "But when he's asleep, El's not going to be in the pool."

"She will if he sleeps now."

"You want me to fall asleep here, now, in front of you all?"

"Yes, Will, if you could."

"Dustin, I can't just sleep on command!"

El looks between them. She knows Will struggles to fall asleep even at night. Late night conversations and movies with the volume turned down low were how they'd got to know each other better once she'd started living with him.

"There will be some of my Mom's sleeping pills inside somewhere," Steve says. "Not sure why she needs them, but anyway! If you take a double dose, that'll knock you out good for a while Byres."

"No," Mike says. It's the first thing he's said in a while and he flushes as everyone turns to look at him. "What? We can't make Will sleep. Not after all the shit he went through before when we had to keep drugging him. It's not fair!"

"It's fine, Mike. I can do it," Will says, although he looks like he's about to cry. "Whatever it takes to stop Vecna, right?"

A look passes between Will and Mike that El doesn't understand.

"Will that work, El?" Lucas asks. "Will you be able to get inside Will's head if he's asleep and doesn't know you're coming?"

"Yes," she replies. "That will make it easier."

"Then I'll do it," Will says, sounding unusually fierce.

As Steve goes to fetch the pills, El watches Will and Mike. They're sitting at opposite ends of the group, not looking at each other, and only speaking when they have to. She wonders if it's about Mike getting hurt by the vines, whether Mike is upset or Will's still feeling guilty, but they'd seemed fine when they'd gone off to find the salt together. Something has changed since then.

There's no time to ask, because Steve returns with the pills and Will swallows them down like he's eating M&Ms. They exchange a quick look, and then Will awkwardly moves into a lying position ready to sleep, so she puts the goggles back on and waits.

She opens her eyes into the darkness of the Upside Down. Pores float in front of her. She moves them aside with a waft of her hand, making it easier to identify where she is. She recognises the structure that her friends call a castle. It had confused her for so long, how this collection of sticks loosely nailed together can be called a castle, the same word as the big places she's seen on TV and in Mike's comics, with towers and ballrooms and a moat. She still doesn't quite understand it, really.

She takes a few steps closer. Given she's in Will's memories, it kind of makes sense she's landed here, in the place they first met, but she doesn't want to open the curtain any more now than she did back then. But just as she had in the past, she does it anyway.

She sees a young Will curled up on the floor, covered in dirt and slime, eyes shut, trembling from head to toe. Behind him, is the Will she'd left sleeping beside the pool, taller, older and yet the two of them look like twins. They're lying in exactly the same position, arms pulled tightly to their chests, shielding themselves, heads bowed in fear.

She watches the two Will's for a moment. Their chests rise and fall at the same pace, and she matches her own breaths to them too. Synchronised. She knows the now-Will so much better than the younger version, had become his friend and then his sort-of-sister, and yet it's the smaller boy she feels drawn towards. She remembers putting her hand in his, and how ice cold his skin had felt.

She crouches down and crawls towards them, shaking the shoulder of now-Will. He wakes gradually, yawning and disorientated, but she sees his eyes change the moment he registers what's going on. He scrambles to a sitting position, his gaze fixed on his younger self.

Her fingers curl around the inside of his elbow. "It's okay."

He's breathing deeply and she thinks he might be about to be sick.

"Will. We need to go."

His eyes flicker to hers but are drawn back to the other Will like a magnet. "We can't just leave him," he mutters.

"We have to." She slips her hand into his and gives his arm a gentle tug. "Time to find 001," she says. "Come on."

Joined by the hands, they leave Castle Byres together. But the thin curtain doesn't lead them to the woods like it should. It takes them to another confined space. Another nightmare from Will's past.

This time, the younger Will is in a hospital gown, tied to a chair, slumped against the binds. Joyce, Jonathan and Mike surround him, crying, recounting memories as Will's eyes go in and out of focus. Hop's there too and she's startled by the difference in his appearance. She misses this Hop. He'd been her protector at this time, her teacher, someone she could argue with and fight without fear of pushing him over the edge. She watches as he zones in on Will's hands, on the tap, tap, tap against the chair leg.

The young Will growls let me go, and she hears 001's voice within it. It focuses her, reminds her what they're doing and why. She registers how tightly now-Will is squeezing her hand. She looks up at him. There are tears on his cheeks. Taking the lead once more, she pulls him towards the door.

They leave one room and enter another, but this time she knows where they are. Hop's cabin. The first place that felt like home. The room's a mess. The camp bed that Hopper slept on once she moved in with him and took over his bedroom, has been positioned in front of the fire with burning hot heaters surrounding it. Will's on the bed, tied up again, fighting to break free. His body forms shapes she didn't know were even possible and the noises that are coming from his throat hurt her ears. She's heard Will scream before but this sounds nothing like it. This is Will and 001 combined, the sounds of an animal. The sounds of a monster.

It's now-Will who drags her away this time, rushing them towards the exit. They run out of the door so fast that there isn't time to notice the drop beneath them. They fall fast, their hands ripped out of each other's grip, and they hit the ground heavily. El lands on her hands and knees and pain rushes through her, the bare skin on her knees grazed, one wrist definitely sprained. She sinks to the floor with a huff, turning her head to check on Will. He's in the same situation she is, sprawled awkwardly but relatively unharmed.

Around them, this world glows red. Flashes of lighting highlight broken parts of buildings in the distance: a staircase, a half-fallen wall, a single door. There's a steady pulse of vines creeping nearer. Crimson dust lines the ground. She recognises the rotten smell, the cold that immediately seems to sink into her bones.

Will shudders. "This… is not one of my memories."

"No," she agrees.

"We're in his lair, aren't we?"

She can feel a frown trying to overtake her face as she nods, and so she looks away, not wanting to pass her trauma on to Will. But he has stood up and is holding out his hand to her. She takes it and let him pull her to her feet. She stares up above them. The red storm rages overhead.

"Over there," Will says.

She looks at him. He's holding his hand to the back of his neck but when he sees her looking, he moves it to point in the mid-distance.

"Are you sure?"

Will nods.

"Okay." She takes a step in that direction.

"No. No!" Will's hand locks around her wrist. "I'm not letting you go in there alone."

She feels a familiar stab of impatience. However many times she explains to her friends that she's the only person who can defeat 001, they still insist on trying to help, putting themselves in danger in the process.

"I know, I know, you're the one with powers," Will says. "But we're inside my head. That must count for something."

El thinks. She decides he might be right. Besides, it'll be easier to protect him if she can see him. "Fine," she says. "You can come."

They walk in the direction Will sensed, taking far slower steps than they would normally, careful to avoid the vines. In the gloom, it's hard to see what they're walking towards. At first, she thought it was more parts of the broken house, and then she thought it was statues, like the ones she'd seen in California that Jonathan had had to explain weren't real people. But as they get closer, she realises these ones are. Or at least, were.

Their limbs stick out at unnatural angles. There are empty sockets where their eyes should be. Their mouths are twisted open in a forever scream. And they're strung up like prizes, like the trophy cabinet in their Lenora school or the dead bodies of pigs in the butcher shop near where they'd lived. 001's winnings.

El thinks of Max and imagines her broken body here too. Her eyes sting with tears. It makes her want to shout. It makes her want to rip 001 to pieces and leave him here beside his victims.

Will's arm brushes against hers. "These poor people," he says, softly. "Are you okay?"

"No," she replies. Her voice is quiet but fierce. "But I'm ready to kick his ass."

Will jerks his head in the direction they need to go. She takes a final look at the dead body of a blonde girl who would have once been pretty and lets the anger propel her forwards. Towards battle.

As they walk, more bodies come into sight. She tries to keep her focus, fearful that if she looks into each face, she'll start crying and never stop. But a sharp gasp from Will stalls her.

He's staring up at one of the victims. The man's chest and stomach are ripped open, gashes up and down his body, and a hole in the middle of his chest. Where his heart should be, she thinks. Although she never met this man, she recognises him from the photo that sits beside Joyce's bed and remembers Mike telling her about how he died. Her own heart feels like it has been pulled out and eaten by demodogs too.

"This is Bob," Will whispers.

She draws closer to him and tries to pull him into a hug, but he feels almost as stiff as the bodies. She remembers him crying after a nightmare, admitting how guilty he felt for the part he'd had in Bob's death.

"He looks… kind."

"Yeah," Will says. He turns to face her. He's pale and his chin is trembling in the way it always does when he's trying not to cry. "El, why is he here?"

She frowns. "He's-"

"Dead, yeah I know. But he wasn't… Vecna'd." Will moves, frantically looking from one body to the next. "None of these were. Look. Shit-" he dashes between more corpses.

El follows, knowing that Will cursing never meant anything good. Her stomach drops. It's Billy. His mouth and chin are still stained black and his blooded vest does little to hide the puncture wounds in his chest. It feels like she's watching him die all over again, can almost imagine he's impaled upon the monster rather than held up by vines around his wrists.

"I'm sorry," she whispers as quietly as she can.

But there's something else. Will's right. Neither Bob nor Billy were killed by 001. Not directly, anyway.

"Hive Mind," she says.

"What?"

"Everyone is here. Everyone killed by the Hive Mind."

Will's eyes widen. "You're right." His chin is trembling again. "That's… that's a lot of people."

"Yes," she says. "A lot."

"We have to kill him, El, before he adds anyone else to his collection."

She rubs at his shoulder, and he leans into her this time, accepting her offer of a hug. His arms around her help her feel better too. "I will," she tells him. "I promise."

They continue past Billy, past many more dead bodies whose identities are unknown, but gradually the number begins to thin, and they pass to another section. In the real world, she would know this as a garden, but 001 has destroyed any flowers that should have grown here, and vines replace them instead. There's a flash of red lightning so bright it hurts her eyes.

And then-

"Eleven," a sinister voice echoes around them.

She jumps. She spins around trying to find him. Her hand collides with Will, who's doing the same, and he grabs onto her.

"Are you here to kill me, Eleven?" 001 taunts.

"Yes," she says, fiercely. "You're done hurting people."

He laughs, long and cruel. "You're right. Almost."

She's back to back with Will, still linked by one hand, the two of them slowly spinning in a silent agreement to locate his hiding place. Will's hand is sweaty. She can feel him shaking against her. She's as scared as he is but she's not going to show it. Not while 001 is watching.

"Where are you, Henry?"

"In your words, I'm… hiding."

"Coward," she spits back.

"No." He sounds amused. "Just a change of plan. You and your friends thought you had the better of me. All you did was give me a new direction. I think this one might be even more fun than the last."

Her heart's hammering so hard it hurts her chest. "What are you talking about?"

"How about I give you a sneak peak?"

Before she has the chance to respond, a strong force throws her backwards. She crashes into a wall. It feels like all the air in her lungs has been expelled. She focuses, tries to push back, but she can feel that 001's stronger and is able to hold her there while the vines do their work, winding their way around her arms and legs and waist and pinning her in place.

Beside her, but just out of reach, Will's in the same situation, vines trapping him. She can do nothing but watch as he thrashes his head from side to side, trying to prevent a vine wrapping around his neck.

A cold mist hits her face and for a moment she can't see. She thinks of Max in Lucas's arms and blinks furiously, trying to clear the fog. When she can see again, the view has changed. She glances at Will and can tell from his expression, that he sees it too. They're in the attic in Creel House, or at least it looks like they are. In front of them, is 001 in his Vecna form and he's on fire, golden flames eating already scarred skin. A bullet hits him in the stomach and he doubles over and for a moment she thinks he's dying. But then she sees where the bullet came from, sees the three familiar figures at the other end of the room, and she knows from what they've told her that this must be a memory.

El watches as Nancy fires bullet after bullet at 001 and he staggers backwards, falling out the window. Again, the view shifts this time. As the body of Vecna falls to the ground, aflame, El's view stays mid-air level with something shimmery. It reminds her of a ghost, like in the movies she's watched with the party. The figure becomes clearer, less transparent, and eventually she's able to see that it's 001, but as Henry this time, the person from the lab that she'd thought was her friend.

He levitates in the air, separate to his physical body. And then he vanishes.

The next thing she sees is Will. Not the Will trapped beside her, but Will from a few days ago, with her and Lucas in the hospital. She sees now what Will saw at the time. Vines around Lucas, just for a fleeting second, but there's something else too. Something she knows Will can't have heard at the time, or he would have been certain to tell her. A ticking of a clock.

Then, they're at the Byres' house in Jonathan's room. The ticking continues. Vines launch themselves at Jonathan and Will follows them, throwing himself at his brother for a rescue that wasn't required. And then, as the ticking gets louder, Mike becomes trapped beneath another load of vines. He's pinned down, a vine wraps around his neck and Will sits motionless and confused.

The ticking stops.

A clock chimes. Once. Twice.

The vision changes. Henry's sitting crossed legged in the middle of Mike's basement. The furniture is upturned and the posters have been ripped from the walls. There's a large burn mark on the carpet. And then, behind the fallen couch, she sees it. Sees them. The bodies of two of her best friends. Dustin and Lucas are lifeless on the floor, limbs cracked, eyes torn out, blood on their cheeks. El feels a scream force its way out of her throat.

Her eyes move back to Henry, the murdering monster, except the person crossed legged in the middle of the floor has changed. It's no longer Henry. It's Will.

Her scream gets stuck. It feels like she can't breathe.

In the vision, Will stands, seemingly unaffected by the deaths of his friends, and climbs the stairs leading from the basement. There's something different about the way he moves. His back is straight and his arms remain stiffly by his side. It reminds her of a doll Joyce found for her after she'd said she'd never had one, who only moved when she made it.

But as he walks through the door to Mike's bedroom, that changes. Will's shoulders relax and he gives Mike a shy smile, and he looks more like the Will she knows. But then Mike grabs Will's hand and pulls him down so that Will's straddling his thighs and holding onto his waist, and then they're kissing. Mike is kissing Will the same way he kisses her, and Will is kissing back like he needs to to survive.

It's Mike who leads them down to the basement, hand-in-hand, and El waits for Will to react, to stop Mike discovering Dustin and Lucas's bodies. But when they spot them, Will seems as shocked as Mike. He falls to his knees. Mike vomits on the couch. They shout and cry and clutch each other in grief. El can't look away, not even to see how the real Will is doing.

She hears the ticking of a clock again, except this time it's sounds like it's coming from inside her own head. She's confused. It's hard to tell what's real and what's a creation of 001's.

But then they're back in the Byres' house again. Will's standing in the middle, arm outstretched. Jonathan floats in the air in front of him, limp and unconscious. Joyce is screaming, pulling at Will, grabbing his arm and slapping his cheeks and begging and pleading for him to stop. But Will ignores her. Jonathan's limbs snap one by one and blood pours from his eyes and he falls to the floor with a crash.

A clock chimes.

Will turns on his mom.

Then they're back in Mike's bedroom and Will's sobbing, hysterical, he got my mom and my brother, Mike. He got them, they're dead. And Mike's pulling him into a hug, kissing the top of his head, holding him tight and rocking him.

Next, they're in Hopper's cabin. It's just her and Will. The television is on, but he's sketching in his notepad and she's sneaking glances of his drawing rather than watching the show. Then the door bursts open and Mike storms through it, shouting. El, get away from him! He drags Will up and shoves him against the wall. Mike's not strong but Will doesn't fight back and she can see the hurt and confusion in his eyes. It was you! You killed Dustin and Lucas! You killed your own mom and brother! He's got you again, hasn't he? Vecna's got you.

That unusual stiffness returns to Will's back. There's that ticking again, although she knows Hop's never owned a clock this loud. Will's head tilts to one side, then to the other with a click of the joint. He raises an arm and Mike's lifted into the air. Mike's conscious, unlike the others, and El can see the terror on his face as he tries to move but can't.

His arm cracks as it breaks and Mike screams in agony. In the vision, El screams too and turns on Will, on 001, but however hard she fights she can't do anything to prevent his attack on Mike. His other arm snaps and then his leg and Mike is pale and sobbing mid-air. His eyes roll back in his head, then the tears streaming down his cheeks start to turn to red. Blood. His fourth limp snaps. His eyes are ripped from him with a loud pop. His body falls limply to a heap on the floor. It coincides perfectly with the sound of another chime.

El screams again, arms out, descending on 001 in Will's body. Her force pushes him backwards, but he hits the wall with barely a thud and he steps forward again with ease. He turns to face her. It's you or me, 011, Will says.

And El, the real El, understands now. Through the connection with Will, 001 is going to take over Will bit by bit until he can carry out his killings using Will's body. The vines were just a start. She doesn't know how she can stop this, but she has an idea of how to prolong it from happening, to give them a chance to come up with a plan.

If they're inside Will's head, she just needs to push 001 back, further away from the surface, making it harder for him to get control. Last time, she failed Max. She's not going to do the same to Will.

She concentrates, summoning her powers, gathering up enough force around her to do what she needs to.

"Will," she says. Her voices comes out strangled. "When I say now, you need to wake up, okay?"

There's no reply. He looks like he's in shock.

"Will!" she prompts. Loudly.

He looks at her. His face is swollen with tears.

"You have to wake up when I tell you to, okay?"

"…okay."

Her body is tingling with the strength of her powers. She focuses them, so that all the energy is in one place and then she aims it at the Will in the vision. It hits him and the scene in front of them flickers. It's Henry again, not Will. El continues with her blast of powers and she sees 001 falling backwards and she relishes the look of surprise on his face just before the vision vanishes altogether.

"Now!" she shouts. She waits, expectantly, but nothing happens. Bits of 001's lair start falling around them. Her heart is pounding in her chest. "Will, wake up!"

"I'm trying!" he shouts back. "The pills…"

A crumbled bit of wall narrowly misses her head. "You can fight them. Do it, do it now!"

She wakes suddenly in the pool. With one hand, she whips the blindfold from her eyes, with the other she splashes around, trying desperately to stay afloat in the water. Strong hands slip beneath her arms, guiding her into a standing position and anchoring her upright.

Beside the pool, Will's on the ground, Mike beside him, holding his shoulder. Will's eyes flutter as he fights against the sleeping pills. A shudder rocks through his body.

"He's going to be sick, get him on his side," Dustin says.

Mike acts quickly and rolls Will over just in time for him to vomit onto the ground. Even then, Mike's hands don't leave him, one rubbing his arm, the other stroking his hair from his forehead.

"What the fuck happened in there?"

El doesn't reply.