The title comes from 'Metaphors We Live By' by George Lakoff and Mark Johnson (specifically chapter 21).

Starts pretty much straight after Lily and Severus leave the carriage containing James and Sirius (as seen in The Prince's Tale of Deathly Hallows)

...

After finding themselves a new compartment on the Hogwarts Express, just for themselves and without any unwanted company, Lily and Severus sat in bad-tempered silence, gazing out the window as the rolling green hills of England swept past. The silence was disturbed by Severus sniffing occasionally, which irritated Lily. She was in a bad mood, and that was only making it worse. For a day she had been looking forward to with such great excitement for years, it had got off to a bad start. Arguing with Petunia seemed to be something that happened naturally, no matter what she did. Whenever she and Petunia argued, her father would shut himself in his study and read old issues of Wisden and her mother would cry.

Severus, by contrast, was easy to argue with. He never fought back or held grudges, just gave her a hurt look and hunched over, his disreputably long hair falling in his face. She supposed it was unfair of her, to take out her anger at the argument with Petunia on him, but it was hard to resist. After the run-in with the two boys in the previous carriage, though, she was feeling a little uncertain. None of her social interactions had gone well. She had a sudden fear that maybe everyone would be like the two boys and Petunia, that she'd be left with only Severus for a friend. Unless he found someone better, more magical than her.

She looked cautiously over at Severus. He was looking steadfastly out the window, seemingly trying to focus on something. He was sniffing occasionally, and his breath seemed to be shaky. He licked his lips and bit at them, blinking furiously. Suddenly curious, she looked closer. Was it just the light reflecting through the glass, or were his eyes brighter than usual? She almost looked away, embarrassed at having potentially caught him on the verge of tears, but a ripple of courage caught her. Her day had started badly, seemingly consisting of nothing but arguments, but he'd been involved in two of them. She knew his father didn't like magic, and his mother had always scared Lily even though she'd never admit it to Severus. It was entirely possible he'd had as bad a day as she had. Her heart softened slightly, determined that they would arrive at their destination cheerfully as they had always dreamed.

She wracked her brain, trying to think of something to say. In the end, the best she could come up with was in feeble response to the conversation they (and those other boys) had had about the Houses of Hogwarts, "I hope we're in the same House," she said, "How is it decided?"

"I don't know," Severus answered quietly, and there was a strange tone in his voice that she'd never heard before when they'd discussed magic and the magical world. It had been one of the topics that Lily could almost guarantee would have him glowing in excitement and wonder, but now he sounded almost ashamed.

"Did your mum say why she thought you'd be in Slytherin?" Lily asked hopefully, wondering if there may be a clue in that, but Severus shook his head.

"I think she was?" he was his only response as he glumly watched the fields of England pass by.

"Like a family thing?" Lily said in sudden concern. The boys from the other carriage had both mentioned family history in relation to the Houses. Maybe that was how it was decided, she reasoned, "But if it's family… What about me?"

"Maybe you get to chose?" Severus suggested uncertainly, looking at her briefly. He still looked deeply unhappy, "I hope you can, and that…" he tailed off, looking away sharply.

"I'll try to be in Slytherin," Lily said fiercely. She didn't quite know what the Houses entailed, but she knew she would rather be in the same House as Severus rather than the other one the two boys from the other carriage had mentioned.

He sniffed again, and Lily continued, "I promise. I'll do my best to be in Slytherin with you. But no matter what, we'll still be best friends, right?"

He looked at her and she could see now that he really was desperately trying to blink back tears. She felt some prick at the backs of her eyes too as he said earnestly, "I'll always want to be your friend," and he might have said more, but to Lily's annoyance the door to their carriage opened at that very moment and a jolly old lady pushing a trolley poked her head in with a friendly smile.

"Anything from the trolley dearies?" she asked cheerfully, her eyes kind. She wore a pink pastel robe, looking effortlessly welcoming with her immaculately curled grey hair. Severus had turned away, returning his gaze to the scenery outside the window. He gave an almost imperceivable shake of his head as he did so, hunching away from the lady and her trolley. Lily looked from him to the lady, and leapt up before the lady backed away out of the carriage.

"Can I have a look?" she asked, uncertain, scrabbling in her brand new, brown leather satchel for the small pouch of money she'd shoved haphazardly in it. She looked at the wares on offer, carefully considering them as the lady watched her kindly. She glanced at Severus, hopeful for a hint or guidance, but he was ignoring everything in favour of the British countryside. He scratched at his head in irritation, as he often did, but steadfastly refused to consider the trolley. Lily considered the chocolate frogs briefly, as chocolate was rarely a bad choice, but she worried about offending Severus by buying him one and she didn't want to eat one alone. Besides, she reasoned, chocolate was chocolate regardless of the shape. Some of the other sweets looked more interesting and easier to share. She steered clear of the cockroach clusters and the blood flavoured lollipops, finding them both to be somewhat unappealing to say the least, and ultimately deciding that the most tempting item on offer was the small packages labelled Bertie Bott's Every Flavour Beans. Jelly beans seemed like a easy option, that could be shared without any hassle. They seemed made to be shared, even. Plus, Lily reasoned, jelly beans were familiar enough that she wasn't too worried, but the promise of many exciting flavours intrigued her. The lady cheerfully told her the price, took her money and gave her a small box.

The lady left as cheerfully as she'd entered, obviously taking the clear hint that Severus would not be buying anything. Lily carefully opened her small box, and gave the jelly beans a considerate sniff. She could not identify any particular scent but noted that the range of colours was fantastic. She moved to the window, and leaned close to Severus, offering the box to him. He looked at her with a hint of repressed suspicion, regarding the jelly beans with an expression of curiosity he seemed to be trying to hide.

"Try one with me?" Lily asked, and to her relief he nodded. They both picked out a bean each, Severus opting for a strangely beige one and Lily choosing a fascinatingly grey-brown bean. With a shared smile, they popped the jelly beans into their mouths at the same time. Reflected in each other's face, they could see equal looks of confusion and regret at having eaten the beans.

"I think," Severus said, as he swallowed reluctantly, "That might have been worm flavour,"

"Mine was dirt…" Lily admitted with a certain hint of disgust colouring her tone. She looked suspiciously at the remaining beans. Slowly, she closed the box up, to consider at a later date. Magical people obviously had strange tastes.

"I've got some parma violets," Severus offered, rummaging in his pockets. He offered her a tube, and she gratefully ate one. The sweet, aromatic flavour was a pleasant replacement for the heady taste of dirt.

"I wonder if they're all so horrible," Lily wondered with a hint of morbid fascination, enjoying her reassuringly normal parma violet.

Severus sucked on his too, before crunching it as he tended to, "I guess the only way to find out is to try some more…?" he reasoned logically, not sounding particularly enthusiastic about testing the remaining beans, "I've got a few more tubes of parma violets, at least. I stocked up," he told her and Lily was overwhelmed with gratitude for something so welcomingly reliably normal. Severus, she had noticed, had a magical knack for acquiring parma violets even though Lily was pretty certain she'd never actually seen him buy any on any of the occasions they'd drifted into one of the various corner shops around Cokeworth. It was a mysterious talent that Lily was only too happy to benefit from.

As the British countryside passed by, the landscape taking on the drama of the north as they wound their way towards the unknown destination, Lily grumpily wondered why the train had to leave from London. Her parma violet finished, she judged it to be lunch time. She did not bother to check the actual time, as her parents weren't there to lecture her on the importance of patience, and she was starting to get hungry. She shoved the unwanted box of Bertie Bott's Every Flavour Beans into her satchel and removed the carefully packed lunch she'd received from her mother. Severus titled his head slightly in consideration at the appearance of her lunch, and she hoped franticly that he had something to eat besides parma violets. He still seemed to be bothered by something, as if something had disturbed him. To her relief, he moved towards his battered satchel, which may once have been either green or black, it was hard to really be sure. From it he withdrew what looked to be sandwiches.

"I got cheese and pickle," she said cheerfully, "Want to go halves?" as they often shared food.

He peeled back one of the slices of bread cautiously, before informing her, "Marmite," and nodding his agreement.

She handed one of her sandwiches over to him, which he carefully placed on the seat. He examined both of his sandwiches, giving them both a cursory sniff, before handing one over to her. She resolutely ate it first, as he turned slightly away from her to eat her the sandwich he'd received from her first. The bread was stale and the marmite was overly strong, but Severus had never given her anything that wasn't safe to eat. She was fairly confident that he had on occasion eaten slightly mouldy bread rather than give it to her, so she would always unflinchingly eat whatever it was he gave her in the knowledge that he always kept the worst for himself. If she refused it, he would reluctantly hand back her much nicer cheese and pickle sandwich and to her that was a far more unbearable option. These sandwiches had clearly been made by his mother. Severus tended to make slightly better sandwiches and meals in general. One of the most delightful aspects of their friendship was the way in which he would constantly be able to find berries or fruit for them to snack on while they were out playing.

"This is only the second time I've been out of Cokeworth," he told her, watching the landscape outside the window as he started to eat his marmite sandwich. Logically, Lily knew that meant his first time leaving Cokeworth would have to have been the trip he undoubtably took to Diagon Alley. It had been a source of frustration that they had not been allowed to go together, and now hearing this she dearly wished they had.

"When we're older, let's go somewhere interesting and far away," Lily said, in between bites of her infinitely more pleasant sandwich. He nodded. After their sandwiches, Lily opened her pack of crisps, glad to note that they were Seabrook's salt and vinegar. She gestured to him to show he was welcome to share them, but he hesitated slightly.

"I've got nowt more," he told her, "I mean to pick some sloes or something, but mum gave me a bath in some horrible chemical concoction so I couldn't," This surprised Lily, as she knew that bath day for the Snapes was Sunday, before church. Part of the reason she knew was because Severus hated it with a passion. He didn't tend to give too much detail about his home life, but she knew that he hated going to church and hated bathing in the cold water after his parents. He reminded her somewhat of the time her grandmother had washed her cat. The cat, which normally kept itself clean perfectly well, had screamed like a demon and scratched everyone it could reach in its unholy fury. It had hissed and sulked in the corner of the bathroom afterwards, dripping and scraggly. Having been unceremoniously dunked into the tin bath this morning, even if the bath water had been solely for him, had obviously ruffled Severus's feathers, leaving him angry. His hair looked to still be a bit damp, hanging in lank chunks and looking unpleasantly greasy, which made Lily wonder about the effectiveness of whatever his mother had used to wash him. She could empathise with his obvious irritation. She accepted the necessity of her twice weekly baths, but she resented every time her mother would finely comb through her hair, tutting, and subject her to a horrible smelling shampoo. This was not helped by the fact that Petunia invariably took the chance to make a disparaging comment about Severus, riling up Lily's temper and and making her mother more annoyed.

She shrugged with a casual, "It's fine, have some. You're my supply of parma violets after all," which made him smile his slightly crooked, toothy smile.

They crunched away at the crisps in comparable silence, the bad temper of the morning fading. This was a relief to the both of them, as arriving in a new environment without the comforting reminder of their friendship would have made the whole experience more intimidating. Severus still seemed to have something on his mind, but Lily waited as patiently as she could. It might be something to do with his family, in which case there was a chance he wouldn't tell her anyway, but she knew by now that pressing him wouldn't make him more likely to tell her.

Once the crisps were finished, Lily considered whether it would be a good move to start reading the Standard Book of Spells she had shoved into her satchel, in preparation for their arrival at Hogwarts, when Severus began to speak slowly and with a degree of reluctance. He seemed to be trying to remember something, almost as if he didn't really want to think about it.

"Me mum mentioned that some families have traditions," he said, and it took Lily a moment to realise that he was probably referring to the boys they had encountered earlier, even if it was in a roundabout way. She hadn't really been paying that much attention to them, and had pretty much put them from her mind once they'd left the carriage, though it was obvious now that they'd struck a nerve with Severus. She waited silently, with a hint of excitement. She knew that Severus's mother didn't give out much information about the wizarding world. From what she could tell, Eileen Snape didn't give out much information or even talk a huge amount, so the small fragments were of especial value. Now they would be able to discover new things for themselves, but for those initial years of their friendship in Cokeworth, their knowledge of this bright new world that awaited them came exclusively from whatever small scraps of detail she chose to impart to her eager son, which he in turn shared with Lily, his whole face glowing with excitement.

"There's some old families that have been magical since the year dot. Ones that are infamous for dark magic and curses, that everyone's scared of them. They all know all sorts of nasty curses practically from birth, it's in their blood. People I - we - should be careful of and not make enemies out of," he continued, not meeting her eye.

Lily digested this information. Both of the boys she they had encountered did seem to be pretty confident and familiar with the wizarding world. She shivered slightly, "But that's not fair," she protested weakly, "I've never learnt any magic, I thought that wasn't supposed to matter…"

"Neither have I," Severus pointed out sadly, "We might have to study really hard to catch up… And stay safe…" he added and she was grateful that he saw the threats of the world so much more clearly than she did. She couldn't quite comprehend what kind of nasty spells the children from magical backgrounds might know, but she had a sneaking suspicion that if they wanted to do harm, the two of them would be fairly defenceless. She once again resolved to avoid the house they'd mentioned - was it Gryffindor? - and hope frantically to be with Severus.

He pulled out of his satchel the book she'd also bought, the one about defending against 'Dark Forces', though hers was a brand new copy and his had a slightly different subtitle to her's, in addition to having what looked like bite marks from what Lily vaguely assumed to be either rats or mice. She didn't think it likely that any of the Snapes had been responsible for the chewing of the book. Together, they poured over the introduction, sitting side by side. Most of the rest of the journey passed with them commenting and talking excitedly about defending themselves from dark magic and evil curses, until Lily realised that they needed to change into their school robes.

Scrabbling, they withdrew their scrunched up robes. Lily's mother had sighed at her and told her to fold it properly, but Lily had just shoved it into her satchel regardless. The instructions had specified that the trunks would be stored in the baggage section of the carriage, and would be transported from there to their dormitories so the belonging they wanted for the train journey had to be packed separately. Her mother had packed her other clothes into her brand new trunk, complete with runic spells to make it light enough to lift easily, but Lily had been left to her own devices for the satchel. Severus, she was amused to notice, had likewise not folded his robe. Unlike hers, it looked to be second hand. He stood up and drew the curtain over the window in the carriage door, so they could get changed without accidentally gaining an audience.

"So, we take everything off and put the robes on?" Lily checked with him, certain of the answer already. She was already removing her yellow-flowered sundress, almost signifying the end of summer to be replaced with the dark cold of the winter that would follow the encroaching autumn.

He nodded, "I think underwear is alright…?" he reasoned, starting to remove his eclectic clothing. Like all his outfits, it consisted mainly of clothes that were old, didn't appear to fit him or even have been originally purchased for him.

"What about socks?" Lily asked, looking at her feet poking out from underneath her black school robes.

Severus paused slightly and thoughtfully pulled his robes over his head. He sat down, stuck his feet out and wiggled his toes in consideration. He was wearing charmingly odd socks, a lacy yellow one on his left foot and a well-darned but far too large grey one his right. Lily could not recall ever having seen him in matching socks.

"Do wizards wear socks…?" he wondered aloud, and they shared an amused grin.

"I hope so," Lily admitted, with a giggle, "Otherwise we're going to have cold feet in winter,"

Severus shrugged, "No one's going to know with the robes," as they looked at each other with repressed excitement. Finally they looked like a real witch and wizard, about to begin their magical education.