Author's Note: Have another story because I'm not already killing myself enough. Any mobile numbers you see are nonexistent. I know this because I checked first.

This was meant to be a 5000 word oneshot when I originally planned it, which just goes to show that I have no self-control. After I hit 18,000 words on my third day of writing it, I realised that it had gone too far for me to reign it in to one chapter.

Credit for James Potter's unique texting style goes, as always, to cgner.

Chapter One: J and P

Text Received from: +447860 681811 (Unknown)

Sent to: +447561 084351, on Tuesday, 16th January 2018 at 6:36pm

...

Unknown: hi there
i hope you're having a pleasant evening this fine january

+447561 084351: Sorry, who is this?

Unknown: i just thought i'd let you know that this morning i found this number written on the wall in the library at school
it said to call you for a good time

+447561 084351: EXCUSE ME?
How DARE you?!
Are you fucking kidding me? Who is this?
If this is Terry Heaney I SWEAR I'll tell Dumbledore what you did with my shoe.

Unknown: no wait
i'm not terry heaney
but let's return to that later

+447561 084351: I can have you suspended for sexual harassment, you know!

Unknown: no no no no wait wait wait!
i'm not looking for a good time!
i mean i am but that's more of a general statement about living life to the funnest
please don't have me suspended my mum will kill me

+447561 084351: Don't you mean 'fullest?'

Unknown: no i meant funnest
i just wanted you to know someone had put your number there that's all i promise
i know i'd want to know if one of my friends was a betraying snake
unless you put it there yourself
i mean no judgement
what you do on your own time is your business

+447561 084351: Of course I didn't write my number on the wall!
As if I'd ever choose to spend an otherwise lovely Tuesday evening warding off creepy stalkers who feel entitled to ask me for a 'good time.'

Unknown: i'll ignore the insult since i can tell you're upset
also i very kindly scribbled out the number
also they didn't even put your name next to it so it's fine
who is this by the way?

+447561 084351: That's none of your business.

Unknown: well fine then
goodbye to you too

"She was horrible," said James Potter, in disgust.

"Who?"

"Wall person."

"What do you mean?"

"She basically took my head off," he expounded, and cast his phone aside as if it had bitten his finger. It landed on his duvet with a satisfying bounce, leaving James's hand free to ruffle his perpetually untidy hair. "All I did was warn her."

"So she's an arsehole. Probably why her number was on the wall in the first place."

"That doesn't mean she deserved it."

"Maybe, maybe not," said Sirius. "But it explains why someone would put it there."

He yawned, stretching out across the floor while his head lolled sideways against the balled-up hoodie he was using as a pillow, the ends of his long, sleek black hair providing a sharp contrast to the plush, snow white carpet. For Sirius Black, most afternoons were spent napping on James's bedroom floor, owing to a combination of crippling insomnia and a fraught home life which generally prevented him from sleeping in his own room at his parents' house. James normally didn't mind allowing his best friend a few hours of rest, and neither did his mother, who insisted upon giving Sirius mugs of warm milk and cinnamon to 'help him study.'

Today, however, James was annoyed and wanting attention, having been placed on the receiving end of a burst of anger he didn't deserve, from a girl he didn't know, and for what he felt was an act of kindness on his part. He hadn't been obligated to warn Wall Person that she was being billed as a lady of the night in the European History section of the library, but had felt honour-bound to do so. The least she could have done was act a bit bloody grateful.

He peeled off one of his socks, rolled it up and tossed it at Sirius's head.

"What the fuck was that for?" said Sirius, when the sock bounced off his nose.

"That girl pissed me off."

"Did she tell you her name?"

"No."

"Does she know who you are?"

"No?"

"Then send her a picture of your knob," Sirius suggested, with a cold smile for the ceiling. He had a macabre sense of humour at times. "That'll teach her a lesson."

"No!" James cried.

"Thought you loved teaching lessons?"

"I do, but I'm not a monster."

James's mother, Euphemia, often warned him that, though she would stand by his side if he ever committed a murder, sending an unsolicited photo of his genitals to a girl's phone was grounds for instant abandonment. She'd also threatened to have his cat rehomed if he didn't learn about periods, and as a result, he had a rather thorough knowledge of the menstrual cycle, for which he had at least expected the cat to be grateful, but much like Wall Person, Algernon didn't give a shit.

Life was often rather unfair, when James discounted the fact that he was wealthy, popular, handsome, academically gifted, and good at most sports. He had his fair share of problems despite what seemed like a charmed existence – unrequited love, a complete lack of any discernible facial hair even though he was two months away from turning seventeen, a cat who refused to run errands for him, a close friend who consistently outperformed him on board game night, and unrequited love, which bore mentioning twice because that was the worst of his problems, and nobody understood his pain.

"I know you're not packing much," said Sirius. "But you can still—"

"Bugger off," said James irritably. He was packing plenty. Or enough. Just enough. Average, surely. "Being an honourable person isn't a stand-in for a tiny knob."

Sirius snorted. "Honourable."

"If Lily Evans had been Wall Person—"

"Any fucking excuse to mention Evans—"

"But if she had been Evans," James continued, thinking of the object of his unreturned affections, a smart, vivacious redhead with emerald green eyes and the prettiest smile he had ever seen. "She wouldn't have snapped at me. She would have appreciated my gallantry."

"I wish you wouldn't talk like a knight of the fucking round table."

"I wish you weren't so desperate to see me take my dick out."

"You know me," said Sirius lazily. "Always game for a laugh."

"Maybe she'll apologise tomorrow, after she sees the wall."

"Christ, would you shut up about it already?"

"Why?"

I put up without enough of your whinging about Evans without listening to you go on about this bird, too."

"I'll shut up when you stop being a boring arsehole and wake up."

"Fine," Sirius growled, and pushed himself up with his elbows. "Xbox?"

"Xbox," James agreed.

And that, for one day at least, was the end of that.

"It's so obvious that Helena did this," said Mary darkly.

Lily Evans scowled at the wall, and fought against the urge to lick her thumb and rub away what remained of her phone number. The wall was probably filthy, and Helena Hodge wasn't worth the fungal infection that might come with it.

She had been itching to come to the library and take a look at her number all morning, but unwilling to let herself be spotted by the school populace in case anyone figured out that the number belonged to her, so she'd cried off with 'a woman problem' during chemistry and taken Mary Macdonald with her for 'support.' Slughorn was an easy teacher to manipulate when one had the need of it, and the male population's collective fear of menstruation did have its uses at times.

Strangely, the person who had texted Lily to notify her of her number's appearance in the library had only scribbled out five digits, but had done so with gusto. There wasn't a chance that anyone would see what had been written beneath, for which, she supposed, she should have been grateful, even if Mystery Texter had implied that Lily had put it there herself.

"Of course it was Helena," she agreed, with a sigh.

"At least she didn't write your name."

"Why would she? She's so convinced that Potter fancies me—"

"Which he does."

"Shut up."

"But I'm right though?"

"It doesn't matter, the point is that if he did fancy me—"

"Again, he does."

"No, he doesn't," Lily countered, with an accompanying blush to mar her pale cheeks and give the game away. "But if he did and she was right, why would she advertise my number to him, when she could advertise it solely to the truly vile and desperate?"

"All teenage boys are vile and desperate."

"James Potter isn't like that."

"You think James Potter isn't like that because you'd happily let him call you up for a good time."

Lily would have retorted with some fact to disprove Mary's theory, but she actually didn't know Potter that well, but for a small handful of surface interactions that she would have forgotten had they not involved him – such as the time they wound up sitting next to one another at the Year 11 award ceremony, or the time he'd tapped her on the shoulder to tell her that her schoolbag was unzipped. Such brief, unimportant moments could hardly provide Lily with the baseline data to concoct a reasonable assessment of his character, but she would often contest that he was one of those people who gave off a good impression.

This was, in some tiny part, because he was hot, but also because Lily fancied herself to be a good judge of people, which was what she used as an excuse to ward off accusations of favouring Potter because she was attracted to him. She may have been a teenage girl with hormones and urges, but she wasn't illogical.

It was mostly because he was hot, really.

"Let's get out of here," she told Mary, and slipped her hand through the crook of her friend's elbow. "Before anyone sees us."

They left the library, much as they had found it, silent and empty, and headed north along a narrow corridor which lead to the girls' toilets, where they would usually hide on the rare occasion that they skived off class. Such instances were usually reserved for big, emotional disasters because Lily was against ditching classes as a rule, but chemistry was one of her best subjects, and a slight on her honour was something she took quite seriously.

"I guess I'll have to apologise to mystery texter," she said, as they strolled. "I might have snapped at him a little."

"How do you know it's a guy?"

"I dunno, it just seemed like a boy."

"You could apologise, I suppose."

"I should, really."

"Or instead, you could claim moral superiority and never be wrong about anything in your whole life."

"That's also an option."

"Atta girl," said Mary sweetly. "Let's sneak outside and get chips."

And that was the end of that.

Until later.

Text Received from: +447860 681811 (Unknown)

Sent to: +447561 084351, on Wednesday, 17th January 2018 at 7:13pm

...

Unknown: so did you see the wall today?
and more importantly how i scribbled your number out?
i mean you don't have to thank me but it would be nice to be appreciated for my heroism
again please don't get me suspended i swear it wasn't me

+447561 084351: I saw the wall.
Thank you for blacking out half of my number?

Unknown: that was so you'd know to believe me

+447561 084351: Was it also you who wrote 'rude!' next to it in red pen?

Unknown: yes
manners cost nothing

+447561 084351: Well, thank you, I suppose.
I'm sorry for having a go at you yesterday.

Unknown: apology accepted
did you find out who did it

+447561 084351: No, but I'm pretty sure I know who it was.

Unknown: ooh who tell me tell me
i love gossip

+447561 084351: Lol okay, Kim Kardashian.

Unknown: i hate that i know who that is
but not that kind of gossip
tell me tell me tell me

+447561 084351: I'm not telling you. You might know the person. You might be allied with the person. You might BE the person.

Unknown: firstly, how can i be allied with anyone we're not at war
also why would i write your number on the wall then scribble it out then text you to tell you about it
that seems like a waste of time
if you won't tell me who tell me why
you can do that without naming names
i'm invested now so you have to tell me something
my mate and i have a bet going

+447561 084351: Wow.

Unknown: i get that reaction a lot
people are very impressed by me

+447561 084351: No, I mean, you have a bet going? Wtf?
Is that supposed to make me tell you, knowing that you've basically turned my personal life into some sort of game?

Unknown: no no wait!
it's just a bet to see if we can guess their motives

+447561 084351: And what's your theory?

Unknown: that you killed their father when they were very young
since then, phantom scribbler has been waiting for their chance to seek vengeance

+447561 084351: That's a pretty vanilla way to seek vengeance for a dead parent.

Unknown: i didn't say they were all that imaginative

+447561 084351: Well, you're wrong.
If it is who I think it is, she did it because she thinks the guy she fancies has a crush on me, and blames me for it, and is generally a dick about it.
To my face AND behind my back.

Unknown: does he fancy you?

+447561 084351: Um, no?
I don't know?
What am I supposed to do, ask him and rub it in her face if he says yes?

Unknown: that's exactly what you do
even if he doesn't fancy you he probably will if you ask him
guys like it when girls are direct

+447561 084351: What makes you so sure that I'm a girl?
And how would you know that, anyway?

Unknown: lucky guess
also because i'm a boy and i like it when girls are direct

+447561 084351: Do you get a lot of girls propositioning you directly?

Unknown: actually i'm going through a tunnel right now so whooooooooosh
your message was not delivered

+447561 084351: Hahaha!
Well, this was an unexpectedly amusing way to spend ten minutes, I guess. Thanks?

Unknown: yeah it was
we should do it again sometime
that really sounded like i was trying to flirt with you i promise i wasn't

+447561 084351: Haha, who is this again?
You never told me.
No, wait, don't tell me! I bet I can guess.

Unknown: i bet i can guess who you are before you guess who i am
i'm dead good at guessing

+447561 084351: Wow, such confidence.

Unknown: none of it unfounded
prepare to lose

+447561 084351: Boy, you have no idea who you're dealing with.

Unknown: you're right i don't
but i will soon
and you will find yourself sorely defeated

+447561 084351: Okay, well, here's an idea.
Since you're so convinced you've got me beaten already.
Wait, before that, I assume you actually go to Hogwarts and aren't just some janitor hanging around the school and reading the walls, right?

Unknown: that sounds fun
but no i'm a student

+447561 084351: Fun?!
What year are you in?

Unknown: 12

+447561 084351: Same.
Okay, so, I'll agree to a contest if you agree that any guesses must be made in person. You have to actually walk up to the person in real life and ask them to their face, because as it stands you could just cycle through a bunch of names until you find the right one and I have to admit to being me.
Also, guessing in person means you can't guess until you're sure.
Otherwise, you'll just embarrass yourself.

Unknown: deal
luckily i am a master detective aka sherlock holmes so this will be easy
but i need to be able to call you something now so we should give ourselves codenames

+447561 084351: Okay.

Unknown: you can call me THE COMMODORE

+447561 084351: I'm not calling you the Commodore.

Unknown: no it's THE COMMODORE

+447561 084351: So your complete aversion to capital letters ends with a nickname?

Unknown: THE COMMODORE moves to the beat of his own drum

+447561 084351: Okay, well, there's absolutely no way in hell that I'm calling you THE COMMODORE
You can call me Jane Doe.
You know, like an unidentified female body.

Unknown: so you ARE a girl?

+447561 084351: Guilty as charged.

Unknown: alright
then you can call me prongs

+447561 084351: Prongs?

Unknown: yeah because
doe a deer
a female deer
boy deers are stags
stags have prongs

+447561 084351: They're not called prongs, though, they're called antlers.

Unknown: well you can't call me antlers
that's just madness

+447561 084351: Haha, okay.
Prongs it is, then.