Disclaimer: JK Rowling invented these characters; she and her publishers own them. I make no money, I'm just having fun.
Ever since the first day of their first year they had shared a pair of desks side by side in no man's land, the very middle of the classroom, Slytherins to the left and Gryffindors to the right. They were an island unto themselves, or, as Professor Slughorn liked to say, a beacon on the hill. From the very beginning they so completely surpassed their fellows in natural talent that Slughorn complained, good-naturedly, that they'd sucked all the excitement from his little competitions. It was pointless to pit them against anyone else, and they would not compete with each other – whenever he tried to make them do so, they would sedately produce identical potions and split the reward. Eventually, Slughorn gave in and simply handed them every honor and prize, uncontested, for five years. Then, the first class of sixth year, Lily arrived early and settled her materials at a new desk in the front row, as far to the right as she could get. She didn't see Snape come in, but once the usual crowd of students arrived and began shuffling to their desks, she caught an involuntary glimpse of him, staring at her from the center aisle. She busied herself with unpacking her bag – he should not have been shocked, at this stage. She'd made her intentions clear all summer. They hadn't spoken once, and every time he'd called at her house she'd set Petunia on him. She had made a firm resolution to ignore him and to avoid interacting in their shared classes, and she only hoped Professor Slughorn wasn't going to make a huge public fuss over the break-up of his star partnership. Her face reddened at the thought.
She glanced surreptitiously toward the Slytherins to see where Severus had settled, and her mouth pinched into a narrow line. He'd made his intentions clear all summer, too, and apparently still hadn't learned when to quit. He was sitting alone at his old desk, dead center of the classroom. He didn't look at her, and she knew he would not approach her. He would just sit there in his stubborn pride, waiting. Making it seem as if their friendship was a matter for her choice alone – pretending he was the constant one, and she the deserter. Well, he could sit there as long as he wanted, and it wouldn't change one thing. He was the one whose choices had wrecked everything they'd shared, and he was the one who had deserted the only things worth fighting for and believing in. He'd thought he could desert those things without deserting her, but he was wrong, and eventually he was going to have to accept that.
He stayed at that desk from September all the way through June, and as their seventh and final year began, nothing seemed to have changed. Regular as clockwork, stoic and silent, all through the autumn he kept it up – even his Slytherin friends had stopped bothering him about it. Then one crisp Tuesday afternoon in early December, Bertha Jorkins saw Lily Evans and James Potter snogging behind the greenhouses, and word spread through the school like wildfire. That Wednesday morning, Snape missed his first Potions class in seven years. When Friday rolled around he walked in, white-faced and calm, and took a seat next to Rosier as if he'd always belonged there. The whole classroom lay between them now, and neither felt it was enough.
Slughorn had been surprisingly tactful about their various stages of estrangement. He had said nothing personal or embarrassing in class, never tried to force them back together, though Lily still got the impression he was waiting for a thaw to arise between them naturally. He had an annoyingly knowing look in his eye at times, especially around Severus, and Snape hated it as much as she did – the one thing they still shared. Slughorn probed them quietly, reintroducing his old competitions, watching them test themselves against each other. He grew extravagant in his praise for her, declaring her a truly artistic soul, while Snape's creations he honored as simply workmanlike. She couldn't believe their professor was actually that blind – Snape was as independent and intuitive as she, and she squirmed over every unjust distinction Slughorn drew between them. She wanted to be free of her old friend, and she felt that all this undeserved praise was trapping her alongside him again, leaving her with no choice but to stay silent and wrong him or speak up and defend him. She wanted to do neither, and actually began to dread Potions class. Snape's own response was no help at all – he sneered behind Slughorn's back and stared at her inscrutably whenever she blushed under false praises. Not once did he speak up for himself or his work. She hated him for knowing her so well, for refusing to stand up on his own account and spare her the pangs of conscience. She could almost imagine that he was secretly clinging to their teacher's slights against him, taking bizarre comfort from the unhappiness they caused her, as if this proved she still cared. The whole situation was maddening, and she tried her hardest to put it out of mind. She had no control over it, and she refused to take responsibility.
One afternoon toward the end of seventh year, Slughorn unveiled his latest competition: to the student who brewed the finest batch of Camordia Amanite, he would present a full day's dose of Felix Felicis.
"I've never offered this potion as a prize before," he chirped to his awed audience. "To tell you the truth, I only recently acquired the tools necessary for its preparation from one of my generous patrons. So I hope you will use it with maturity and legality, and not give me cause to regret my generosity."
Generosity, indeed – it was fiendishly difficult to brew, and required a load of specialized equipment. Lily was uncomfortably aware of her classmates' stares – everyone knew this was really between her and Snape, and these days that meant a Gryffindor-Slytherin showdown. She was sick to death of it. Angry but determined, she set to work, ignoring every distraction around her. After an hour, events played out as she'd known they would. Her potion simmered, lilac and flawless, with the scent of peppermint wafting from its depths. Snape's work matched hers in beauty and tone, odorless and rippling silkily, and he'd somehow managed to finish it a good five minutes ahead of her. Both were picture perfect, but Slughorn practically composed an ode to her peppermints – apparently a stroke of genius rather than a stop-gap remedy for a low supply of bicorn powder – and handed her the dancing, sunny prize. James beamed at her, and she felt wretched that her teacher's pointless favoritism was robbing her of the chance to honestly share this joy. Her potion had been perfect, the prize was magnificent – why couldn't she feel pleased?
She bent to begin packing up her ingredients, and made a frustrated decision.
"I'll meet you at Transfiguration," she called over to James, who frowned in mild confusion but thankfully didn't argue. As she'd expected, Snape glanced up at the sound of her voice, and she caught his eye. An obscure guilt crept over her as he stopped and stared. His eyes held surprise and an awful hopefulness that he couldn't quite mask. She frowned, but held his gaze a second longer before turning to pack up her supplies, moving slowly and deliberately. Once the classroom had emptied and Slughorn had disappeared into his office with his usual delicate sense of timing, she looked up again and found that her old friend had gotten the message. He was still at his desk, slowly brushing the last of his crushed billywig into its case, watching her. Uncomfortable, she threw her bag over one shoulder and approached him, the Felix Felicis sparkling in her hand. Stopping a safe distance from him, she held the bottle out. He looked at it, and a crease appeared between his eyes.
"It's yours," he said. "Your potion was perfect."
"So was yours. He still hasn't figured out you're as good as I am," she answered, and it was the first personal thing she'd said to him in a year and a half. "He was being unfair. We should split it."
She shook the phial a little bit in an insistent, impatient way, and she saw the unpleasant light of greed enter his face as he stared at the dancing brightness. She could see that he was imagining the uses to which he would put twelve hours of perfect luck, and she was seized by a sudden, sick apprehension. Whatever dreams Severus Snape might have these days, she felt sure they could mean nothing good for her or the people she loved. Dark Magic, pureblood fanaticism…Merlin only knew what he'd do to James…and could this potion affect her, too, without her knowing it? Would all her resolution and the firm walls she had built between them be broken down in a day, or an hour, if he wished it? Her hand twitched involuntarily, and she was filled with regret for her offer – more than regret. She stared at her old friend and was afraid of him for the first time. Yet, somehow, she could not retract her words. Some instinct, some sense of honor, some last thread of trust kept her from taking it back, kept her from denying him the reward he'd earned.
His eyes, fierce and covetous, finally seemed to release the shining potion and take in her trembling hand. With a start he looked up, stepped toward her and stared into her face. She had forgotten how he could look through her when he wished, how he could read her feelings when he had the courage to try. She knew he sensed her fear now, and that he guessed its cause, and she blushed and lowered her eyes. She wished he would just take the potion – all of it, if he wanted. She wished she could just leave and worry about the consequences later. And, most of all, she wished never to find herself alone with him again.
"Lily," he whispered, but she would not look up. She started to move her hand toward his desk – she would just set the vial there and get out. It would be worth the loss of her prize.
His hand closed over hers, gently curling her fingers around the phial, enclosing it in her palm. Its glass was cool against her skin, and his bony, calloused fingers seemed warm only in comparison. For just a moment, they were touching and they were alone and, for once, he was going to do the right thing.
"Keep it," he said. "All of it."
His fingertips lingered lightly against her knuckles, and she drew back. He let her, dropping his hand. Her surprise and relief held her still for a few seconds, then her sense of discomfort came crashing back and she hurried toward the door with barely a nod to him, slipping the phial into her pocket.
"Thanks for finally giving me a choice," he called after her.
She turned in the doorway, frowning. "What's that supposed to mean?"
He slung his bag over his shoulder but made no move to follow her. "It means that when you give me a choice, I choose you," he said calmly. "You haven't offered me one in a long time."
She glared at him, and found that twenty-two months hadn't cooled her anger. "You had five years to choose, Severus, and you've had nearly two more to think things over, and that's as far as you've gotten?" He flushed angrily. "You didn't choose me," she went on, "but the real point is that you can't choose me, not me alone. You have to choose more than me, Sev. Once you're ready for that, then we'll talk."
He stood by his desk, but even from halfway across the room she could see the hand gripping the strap of his bag turning white with sudden pressure. "I don't understand you…I cannot understand you," he said, and he was losing control of himself just as he'd used to, spitting out words like they were poison he could no longer hold inside. "For mercy's sake, just tell me what you want!"
And this was the boy she knew, enraged and helpless. This was the heart of him, her oldest friend, with all defenses down – incoherent and uncomprehending, and, somehow, always in pain.
"I just told you," she said. "I want you to choose a different path." He looked at her hopelessly, and she felt her anger fade to its usual dull ache. He really didn't know what she was talking about, couldn't imagine what she wanted him to do – he was that far gone. She shook her head and turned to go, ignoring his quiet groan. As she did so, she felt the weight of the phial in her pocket, and paused once more.
"You were generous, just now," she said softly. "You were lovely, really. But it didn't get you what you wanted, so it seems unfair to hold you to it." She lifted the vial one last time. "Would you like to change your mind about this?"
Snape looked sick. He glared at her, and his mouth was a narrow gash across his face. "Just go," he said.
"You really don't want it?"
"What I want and what I can have are two very different things, as you've made abundantly clear," he snarled, finally moving to cross the classroom himself and brushing past her. He muttered his final words under his breath, so softly that she did not hear. "And no, that is not what I want from you."
Lily kept the potion, all of it. It seemed a strange and bitter parting gift, but also strangely appropriate. Over a year later, she and James drank it together and defied Voldemort for the first time.