A/N: Yeah, you know how it goes, shouldn't start new shit until my old shit's done, but here it goes anyway...
Prologue
The butterfly flaps its wings
Sometimes – not as often as people imagine, but often enough for it to count – the smallest incident might change the course of history. Of course, most of the time that does not happen, but it might still change the lives of several people. The incident that sets off this story, however, is the kind that does both. Depending on its outcome, history will take different paths, but it will be the way it changes people's lives that will matter to them. But what outcome is for better or for worse... that's for you readers to decide.
It's 1971, and Severus Snape and Lily Evans are on their way to Defence Against the Dark Arts. It's their second week at Hogwarts, and they're already learning what it means to be a Slytherin and a Gryffindor trying to be friends. Severus is trying to make friends with his the boys in his class so that he'll have protection against those taking offence at him spending time with a mudblood. Lily is trying to make friends with the girls in her class so that she won't have to be all alone, in case he decides that he doesn't want her around anymore. But they still don't have any other close friends except each other, and it's hard for them not to have someone to talk to about what their classmates say about people from their best friend's House.
Today, however, they are both in a good mood, because there was pie for lunch and they both like Defence, though for different reasons. They are chattering happily and waving their wands around in what they suppose to be fighting stances, when they were interrupted by a shredding sound followed by a series of thuds. Lily's rather old, tattered bag that she had absolutely refused to replace has finally given up and ripped along a seam. Her books are all over the floor, bathing in an expanding puddle of purple ink.
And right here, Lily is given a choice with two alternatives. The first alternative is to decide, rather uncharacteristically, that she needs a new bag for the rest of the day. If she makes that choice she bids farewell to Severus and hurries back to her dorm and out of this story. Severus walks on, and when he encounters two Slytherin third-years harassing a Gryffindor student he just hurries past without looking. He has enough troubles on his own without making enemies.
But we already know how that story ends. If Lily decides on the second alternative, however, she will grab her books from the floor, swear quietly over the state of them and hurry off to class, hoping that Professor Fortescue will be able to do something about them. And when the two of them walk in on the two bullying Slytherins, Lily stops dead in her tracks. Severus hesitates a few seconds before he, too, slows down. He wishes he wouldn't have to, but Lily's opinion means everything.
"What are you doing? Stop that!" Lily crosses her arms and narrows her eyes. The Slytherins turn their heads, chuckling and nudging each other as they notice the short first-year girl glaring at them. One of them grabs her unfortunate classmate and pins him against the wall, the other one advances on Lily and Severus. He has wavy blond hair and eyes just as green as Lily's, only fairer.
"Or what?" he drawls, playing pointedly with his wand. Lily doesn't even flinch.
"Or I'll tell the first professor I see," she retorts angrily.
"You wouldn't dare," he snorts back at her, and now the wand tip is pointed at her.
Lily lifts her chin. "What would be the point of being a Gryffindor if I didn't?"
The two third-years laugh. "Yes, because we're so impressed by the Gryffindor courage," sneers the one who's still holding their victim pressed against the wall, pushing harder. The boy, already in tears, whimpers and squirms, provoking more laughter from the Slytherins.
"Besides, you don't know our names, so you can't report us," the first one adds.
"Avery and Greengrass, third year, Slytherin." Severus' voice doesn't shake, but behind his back he's bunching up his hands in tight, tight fists.
The bullies' eyes snap to him, narrowing in anger, but Avery finally lets go of the captured Gryffindor, who slides to the floor and then scrambles out of the way.
"Helping out your pretty little girlfriend, are you? There's a nasty word for Slytherins who snitch on other Slytherins."
"Yeah, traitor," Greengrass hisses, enunciating clearly for more effect.
Severus looks away, but Lily beams at him, ignoring the other Slytherins. "Thanks, Sev." Then she turns and smiles at the Gryffindor boy hovering uncertainly at a healthy distance from the bullies. "Peter, isn't it?" The boy nods. "Come on, then, let's go to class or we'll be late." She touches Severus' arm, indicating that he should unfreeze from the floor and follow, and as always, he does. So, after a moment's hesitation, does Peter, throwing a frightened look over his shoulder at the two Slytherins. But they've lost their interest in him. Instead they glare at Severus' retreating back, shouting a last, 'Traitor!" after him before the first-years manages to get out of sight. Then they look at each other, shrug, and leave for the library. On the way they encounter three Gryffindor boys running helter-skelter down the corridor, laughing and shouting amongst each other, good-naturedly trying to place the blame for their obvious lateness. If Lily hadn't intervened, it would have been they that would have found Peter and rescued him.
But as I said, we already know that story.
A/N: Will hopefully update soon, because this was rather short, wasn't it?