I have an entire forest living inside of me and you have carved your initials into every tree.

1981

Two years after the birth of their first son, John and Mary Winchester move their family from Lawrence, Kansas, to the small town of Sioux Falls, South Dakota. It takes them five and a half hours to drive 385 miles north, and toddler Dean sleeps the whole journey. The small two-story house that will become their new home is at the end of the street, has a large front lawn and a small back yard, and neighbours with whom they will become close friends: Naomi Novak, and her three-year-old son Castiel.

1982

Mary and Dean are playing in the back yard when the phone rings. She leaves him alone to answer it. Not three minutes later she comes back to find her son gone.

She runs into the street and screaming Dean's name, but he doesn't come running. Tears flowing down her cheeks, she knocks frantically on Naomi's door. John is at work and she needs someone who'll understand her panic.

Naomi has never moved faster in her life than in that moment, racing to check on her own son, only to find Castiel still playing in the sandpit where she'd left him.

Dean is with him.

Mary is too relieved to be angry with him for toddling off on his own. She doesn't tell John, but makes sure he fixes the broken latch on their gate.

1983

Six months after the birth of their second son, John dies saving their children from a fire that almost claims their home. They move in with the Novaks until the repairs are completed.

1984

Dean starts school. He cries when he finds out that Castiel isn't in his class.

. * * * .

"Maybe I'll be in your class today," he tells Castiel hopefully as Mary walks them both to school on their second day.

When she explains that they'll be in separate classes all year, Dean bursts into tears.

"I want to be with Cas!" he wails at the gate as Mary tries to shush him.

"I'll eat lunch with you," Castiel promises.

Dean sniffs. "Promise?"

"I promise."

"Every day?"

"Every day," Cas nods solemnly.

As Castiel takes Dean's hand and walks him up the path to the school building Mary can't help but smile, even if one or two of the other parents shake their heads and tut disapprovingly at the sight of the two young boys holding hands.

1985

When Naomi's brother dies unexpectedly, she asks if Mary will look after Castiel while she goes out of state to prepare the funeral. She warns her that he suffers from regular nightmares, so if he wakes up screaming in the middle of the night they shouldn't be alarmed.

Though concerned that Castiel's nightmares may upset Dean, Mary still makes up the camp bed in Dean's room as planned and kisses both boys goodnight. When she goes to wake them up in the morning, they're both snuggled together in Dean's bed. The camp bed remains unslept in as Cas spends every night in bed with Dean. He doesn't have a single nightmare.

. * * * .

"Dean?" Castiel's voice whispers in the darkness.

"Yeah, Cas?"

"Will the monsters find me here when they realise I'm not at home?"

"There's no such things as monsters, Cas," Dean tells him, echoing his father's words when he told him he thought there was a monster in his closet.

"Yes, there is," Castiel pouts.

Dean bites his lip, then shuffles over in his bed. "You can sleep with me if you want. I'll keep the monsters away."

"Really?" Castiel asks, his voice hopeful.

"Really," Dean tells him, leaping out of bed and rummaging in his toy chest until he finds his toy lightsaber. "If any come, I'll hunt them down." He spins and twirls like a Jedi, making noises with his mouth as he waves the lightsaber around. Castiel giggles and Dean flops back down on his bed again as he tires himself out and places the toy across his bedside table.

Castiel crawls into bed with him. He falls asleep long before Dean, who stays awake for as long as he can keep his eyes open; just in case his dad was wrong.

1986

Naomi and Castiel have taken summer vacations before, but this is the first time they've gone away for the whole summer. Dean's utterly miserable without Cas because they've always been inseparable, and there's nothing Mary can do about it. He's still got his little brother, but Sam's a bit too young to play with. Cas does send them a postcard every couple of weeks, however, and the mornings they arrive is when Dean smiles the brightest.

He's even happy when it's time to go back to school, because at least he has Cas again. But when he comes home from school in a foul mood one day, and all Mary can get out from him is that, "Girls are icky!"

When she talks to Naomi later that evening, it turns out that Cas got into a bit of trouble for kissing a girl at school that day.

1987

In the playground some of the girls are holding weddings for each other under tress from which blossom falls like confetti. Dean and Castiel ask if one of the girls will marry the two of them, but they laugh and tell them that boys don't marry other boys.

Girls aren't just icky, he decides. Girls are also mean.

1989

Mrs Talbot invites everyone in her daughter's class to Bela's 10th birthday party. Nobody there talks to Cas, because everyone in their class thinks he's a little weird. Dean spends the whole afternoon sitting with him at the table, eating mini pizzas and sausage rolls and chips, even though he really wants to play on the bouncy castle Bela's mother hired.

. * * * .

"I'm weird," Castiel tells Dean, spraying chewed up bits of sausage roll everywhere.

"No, you're not."

"I am," Cas insists. "Everyone says so."

"Everyone else is wrong," Dean argues. "They're the ones who're weird for not seeing that you're the coolest person in our class."

"Maybe the second coolest," Cas smiles shyly, "because no-one's cooler than you."

Dean hugs Cas, launching himself at his friend so hard that they both fall off their chairs and the loose tooth that Cas has been twisting around in his mouth for the past two weeks is finally knocked out.

1990

Mary hasn't touched the garden in more weeks than she'd care to admit; the flowerbeds are a carpet of green weeds, there are several dead flowers hanging from her plants, the hedge needs cut back, and there's a broken branch hanging from the larger tree that needs to be removed before it falls on someone's head, so the boys are only allowed to play in the front yard for now.

As she cuts back one of the bushes, she finally discovers where the missing tennis racket has gone. She pushes branches out of the way and retrieves it, resolving to give her sons a scolding for throwing their toys into the bushes. As she turns to make her way back onto the grass, some scratches in the tree catch her eye. Upon closer inspection, she sees the letters DW and CN etched into the bark, surrounded by a heart. The marks look old, so no matter what age Dean and Cas had been when they'd carved them, they would have been too young to be handling knives - especially unsupervised.

She can't bring herself to be mad at them, however, and vows to herself never to be gender specific whenever she talks to Dean – or even Sam – in the future when it comes to talking about dating 'a person', though she never assumes their childhood feelings mean anything.

. * * * .

Two years earlier...

"Will we get into trouble?" Castiel whispers.

"No," Dean promises. "Not if you don't tell anyone." He cries out as the knife in his hand cuts his skin, and a faint line of red blossoms to the surface.

"We should stop."

"I'm finished." The letters D and W are now engraved on the trunk of the tree for all eternity. Dean passes the knife to Cas. "Your turn."

Castiel carves his own initials, the curve of the C harder than the straight lines of the N, with his bottom lip firmly between his teeth as he concentrates.

When he's finished he passes the knife back to Dean, who adds a heart around the letters. "There," he says proudly. "Now we don't need to get married."

1991

Mary's at work when she gets a phone call from the school principal asking her to come in, because Dean started a fight and is being suspended. She has no choice but to ground him, meaning he's not allowed to see Cas for a week. She feels more guilty than she probably should - after all she is the parent and Dean needs to be disciplined because his behaviour was unacceptable - but from Dean's anguish it feels like she's split up two halves of a whole.

. * * * .

"I didn't start it!" he complains once they're driving home from school, a week's worth of homework in his bag. "Alastair was calling Cas horrid names, so I shut him up."

"Did he hit you before you hit him?"

"No."

"Then you started the fight, Dean. I raised you better than that."

"You raised me to stand up for people," he points out.

"Castiel can take care of himself," she tells him. "He doesn't need you to look out for him."

I've been looking out for him since he was seven and he thought there were monsters under his bed, Dean thinks.

1992

Now that Dean is in his teens, Mary trusts him to take Sam down to the park. He and Castiel take him there every day after school, and she knows she's lucky that her two boys rarely fight. But when Sam jumps off the slide one day and breaks his arm, Dean cries more than Sam does.

He cycles back from the park with Sam on his handlebars while Cas runs along side them, then she drives them all to the emergency room. While she goes into the examination room with Sam, Castiel calms Dean outside. When they arrive back home several hours later with pizzas for dinner, Dean and Cas take out their colouring pens and decorate Sam's cast.

. * * * .

"It's all my fault, Cas," Dean sobs while his brother is getting examined.

It's not your fault, Dean," Castiel growls. "You didn't push Sam off the slide - he jumped."

"He did it because I did it! If I hadn't then he wouldn't, and Sam wouldn't be hurt!"

"Your mum doesn't blame you, so you shouldn't blame yourself. They'll put his arm in a cast and he'll be fine."

At that moment Sam appears with his arm in a white cast, as Cas had said, and sucking a green lollipop.

"I'm sorry, Sammy!" Dean shouts, jumping out of his chair and running over to his brother. "I'm so, so sorry!"

"I got a lolly for you, too," Sam smiles, holding a red one out to him.

Dean ignores it, instead throwing his arms around his younger brother and burying his face in his neck.

When Castiel rushes over to hug him as well, Mary thinks that it must appear that she has three sons. "Come on, let's go home," she tells them. "We've been here so long I haven't had time to cook, so what do you boys say to pizza?"

"Yeah!" three voices cry in unison, and she laughs. They have a take out menu in the glove box, which the three of them pour over in the car as she drives.

. * * * .

"Move over, Cas - I want to draw our car there!"

"I thought we were supposed to be drawing things Sam likes?" Castiel asks, amused.

Mary doesn't mean to eavesdrop as she gathers their glasses and empty pizza boxes.

"Well you can draw things Sam likes, but I'm drawing things I like," Dean shoots back.

"What's that?" Sam asks, pointing to a pink circle with two blue dots and black spiky bits.

"That's Cas," Dean grins, as he adds a red line for his mouth.

"That looks nothing like me," Cas tells him. "Why am I not smiling?"

"Because you don't smile."

"I do smile!" Castiel protests.

"You're always so serious," argues Dean.

"Do you like Cas?" Sam interrupts.

Dean laughs. "Duh!"

1993

The school arranges a trip to Washington DC. Dean is excited to go but Mary is worried, because he's never been away from home before. She worries less about him, however, when she finds out he'll be sharing a room with Cas. She drives him and Castiel to the airport, where she waves them off. Naomi will bring them home at the end of the weekend.

While Dean's away rushing around after Sam keeps Mary busy - he's going to the cinema with Chuck and Becky, ice skating with Ruby and her family, and swimming with Kevin. She hardly has a spare second to think, but when she does she worries about Dean. She isn't sure how she'll cope when he leave home for good, but before she knows it he's home again.

Naomi's car has barely come to a stop in the driveway before Dean bursts into the house with a massive grin on his face and wraps his arm around her. "I missed you," he whispers in her ear.

Castiel follows a minute later with Dean's suitcase, and Mary berates Dean for not carrying his own luggage before hugging Cas, too. They have hundreds of photos to show her. It hits her then just how much Castiel has become a part of their family. Dean swears he saw President Clinton on their White House tour. "Why does he need to take a tour of the White House when he lives there?" she jokes, but he doesn't find her funny.

She finds out from Castiel that Dean held his hand the whole way there and back – four hours each way. She's never known her son to be afraid of anything – but it turns out he's afraid of flying.

. * * * .

"Statistically speaking, flying is the safest way to travel," Cas tells him, obviously trying to be reassuring.

"If people were meant to fly they'd have wings," Dean shoots back through gritted teeth.

As the plane jolts through a rather nasty bit of turbulence, Dean squeezes Castiel's hand even tighter. He doesn't notice that Cas winces, and Cas says nothing.

1994

Mary wonders if it's normal that Dean hasn't started dating. When she airs her concerns to Naomi, she tells her not to worry because Castiel hasn't started dating either.

She thinks about the initials on her tree, and wonders if the two are connected.

1995

Nothing lasts forever. That's what Castiel tells himself when he sees Dean laughing with Alastair and his mates. He remembers when Dean had exchanged punches with Alastair instead of laughs. Cas doesn't know what made Dean change, or what he did to push his only away, but he misses him; misses their friendship. He knows Mary is concerned, but if she knew what Dean was really getting up to she'd be a lot more worried. For now Dean narrowly avoids getting into any serious trouble, but surely it's only a matter of time before his antics escalate?

Sometimes Cas finds himself staring out his bedroom window at Dean's, thinking of all the night's they'd shout 'Good night! at each other across their driveways, much to the irritation of their parents and other neighbours. The fondness he feels for those memories is accompanied by a dull but persistent ache. No matter how much Dean has hurt him over the past few months, he knows that if Dean ever asked him for his help he couldn't say no. After all, what are best friends for?

. * * * .

On a night Cas is staring wistfully at Dean's closed curtains he witnesses him sneaking out the back door, through the yard, and hopping over the fence. He should go downstairs and phone Mary, but he still hangs onto the hope that he can repair their friendship and doesn't want to do anything to damage it further, so simply goes to bed.

Some time later he's awoken from his sleep but a dull buzzing. It's a message from Dean.

In sn usuit.

Dean must have been drinking again.

Castiel frowns as he tries to translate it, miming typing the letters over his keypad. I'm an idiot. Well, that's got to be the understatement of the year.

Where r u?

Ttees.

Was that supposed to mean titties? His phone buzzes again.

Trres. Skide. Sam.

Trees? Slide. Sam. Castiel looks at the time. After 2am. Sighing he throws back the covers and gets dressed as quietly as he can, before tiptoeing out of the house.

As he guessed, he finds Dean in the play park where Sam broke his wrist. Also, but not entirely unexpectedly, he's throwing up.

"What are you doing here?" Dean growls.

"You texted me."

"Yeah, but why did you come? Why they hell do you still care about me when I've been treating you like shit?"

"Because we're friends," Castiel answers honestly.

"Are we? Are we still friends when I haven't spoken to you in..." Dean trails off as he tries to count out the time on his fingers.

"Five months," Castiel tells him. "It's been five months."

"'M sorry."

"You've always looked out for me. Now it's my turn to look out for you."

Dean stares at him

"We look out for each other," Cas repeats, "even with the other is being an idiot." He hauls Dean to his feet and gets fresh vomit on his shoes for his effort.

1996

When it's Grandpa Campbell's birthday Mary and Sam go to visit him for a few days, but because Dean has exams to study for he's allowed to stay at home alone - though Naomi will be keeping a close eye on him. When she goes to her church bingo night he invites a few friends over - with his mom's permission - to eat pizza and listen to music, but then more and more people he's never seen before start turning up. It accidentally turns into a massive party that he has no idea how to stop, until Castiel pulls the plug - literally. The house plunges into deafening silence and Cas takes control, ordering everybody out.

Dean can't ever admit to his friend that he was a little turned on in that moment.

. * * * .

"Thanks, dude," Dean says, as he throws paper cups into a garbage bag. They didn't even have paper cups, so where they hell did they come from?

"The music was giving me a headache," Castiel says dryly.

Dean laughs. "You know you can go home. You don't need to stay and help clean up."

"I want to."

"You want to?"

"I don't want Mary to ground you."

"Don't jinx it. How the hell am I going to explain this to her?"

"Try explaining it to me, first," Naomi says icily, standing in the doorway.

"I... We... Uh..." he stutters, unable to string two words together. Mrs Novak is terrifying when she's angry. Dean's glad she isn't his mother. Thankfully the conversation with his own mother goes much easier.

"You let me down," Mary tells him when she gets home, and Dean's stomach twists.

"You said I could have a few friends over," he reminds her quietly. "It wasn't a party - just some of us hanging out. But then strangers started turning up, so we ended it."

Her stern expression softens. "Is anything broken?"

"No. At least, I'm pretty sure it's not. We didn't find anything when we cleaned up."

She looks around and chuckles. "It's not often the parent of a teenager can say they've come back to find the house cleaner than they left it. Is it safe to say you've learnt your lesson about not throwing any more wild parties?"

"Hell yes."

1997

Dean's senior prom is approaching, and as far as she knows Dean hasn't asked anybody yet. Every time she asks him about it he snaps at her, so one afternoon she bakes a pie. If there's one way to get Dean to talk, it's to tell him he can't have any pie until he does.

At first he storms off to his room, which tells her there's something really wrong, but an hour later he relents and confesses that he wants to ask Castiel to prom but is afraid that whatever it is he feels for his friend is one-sided.

A great weight is taken off her chest as she tries to offer him advice, because if there's anyone she trusts with her son's heart it's Castiel.

. * * * .

A couple of days later Dean brings Castiel back to his house after school, which isn't unusual.

"I want to show you something," he tells him, dumping his schoolbag on the floor where his mother will inevitably yell at him for leaving it. He goes out into the garden – never checking if Castiel is following because he follows Dean everywhere – and rounds the big tree at the bottom, ducking under a thick branch and brushing several smaller ones out of his way, so he's standing in front of their initials. "Do you remember carving your initials beside mine?" he asks, playing it off like he doesn't care if Cas doesn't.

But Cas smiles as he traces the heart with his fingers, long and tanned, ending in perfectly trimmed nails. "Of course I do. This is my favourite memory."

Dean stares at him, because Cas has done a load of cool stuff in his life. His mother is well-off and has a holiday home in France, where Cas has been drinking wine since he was twelve. He's visited the Egyptian pyramids, trekked Machu Picchu, and gone scuba-diving along the Great Barrier Reef. But this... this is his favourite memory? Carving his initials into one of the Winchesters' trees when he was nine years old?

Castiel's cheeks redden as he becomes aware of Dean's gaze, and his hand drops to his side.

Dean had a whole speech rehearsed if this went well, but now he can't remember any of it. It doesn't matter, though, because the expectation that his feelings are unrequited has been replaced with a spark of hope; a hope that grows every second Cas avoids his gaze. Taking a chance, he leans in a little closer.

Finally, Cas looks at him out of the corner of his eye.

Dean cups a hand along his jaw, turning his face towards him.

Castiel's breath hitches; his eyes dropping to Dean's mouth when his tongue runs across his bottom lip.

He rubs his thumb across Cas's cheek, the stubble from where he hadn't shaved that morning prickly, as he presses their lips together.

There's a second where Cas doesn't respond – freezing in place – and Dean can swear his heart stops in that moment; but when he grabs onto Dean with both hands and kisses him back a strange sense of calm flows through him, that tells him everything's going to be okay.

. * * * .

As Dean and Cas walk into the house together, half an hour after venturing out into the garden and with leaves in their hair, Mary tries to catch her son's eye. When he looks over at her and smirks, giving her the smallest of nods – as if she needs him to tell her things are good when he has Castiel's hand clasped tightly in his own – she smiles to herself.

"Is Cas staying for dinner?" she asks, stopping Cas in his tracks.

"Yeah," Dean tells her, trying to drag him towards the stairs.

"If that's okay," Castiel smiles at her.

"Of course it is, Cas," she assures him. As he follows Dean upstairs she's already planning what she can make for dinner. There may only be four bodies at the table tonight, but Sam is growing and eats enough for two these days.

1998

Castiel goes to university and Dean goes to college, but they make arrangements to share an apartment together. it's here that they exchange their first Valentine's Day cards.

Castiel's card to Dean is overly-sentimental with five pages of over-the-top romantic poetry that makes Dean want to vomit, and it takes him three full minutes to read it all.

Dean's, on the other hand, isn't even a real Valentine's Day card. It has a photo of George Washington National Forest on the front; the 'blank inside for your own message' sticker still on the front. Inside, Dean has scribbled, "I have an entire forest living inside of me and you have carved your initials into every tree."

Cas frames it and places it on his bedside table.

2017

Two years after same-sex marriage is ruled a constitutional right, and ten years after Cas accepted Dean's nervous proposal, Mary Winchester makes a scrapbook of all these memories and more as her wedding present to the two grooms. She leaves many pages blank for them to fill with all the memories they've yet to make.