Severus Snape had always walked the tightrope between dark and light. At ten years of age, he turned stone over sky to find Lily Evans, to tell her that she was a witch. They spent the day on the grass, watching chubby clouds chase each other and looking forward to Hogwarts. Even at ten years of age, with no moonlit Patronus leaping from her wand, Lily Evans resembled much of a doe: affectionate, chaste, and most of all, whiter than snow. She was fierce, wild, furious, blinding. She had green eyes brighter than gems, and she drew him to her like moth to flame.

Back home, his father hurled insults and his mother sat like a sculpture at the dinner table. The poison of the household bled into Severus slowly, insidiously, and he found himself tainted and hurting at an impressionable eleven.

He was a solitary child, wandering the Hogwarts corridors alone, seeking peace with potion cauldrons. He was cursed with gifts too heavy to bear—he could brew death and bottle fame, could feel the magic as a pulse in his veins, could dream of curses that turned skin bloody, could do everything above at once in his purest loathing. Under the sweeping willow trees, Severus Snape was a creature of trespass, teetering on the precipice of damnation, enduring the jeering taunts of James Potter and the humiliation that it brought to his name. In the dark, without Lily's golden light to guide him, he muttered spells so heinous that they brought him to favor with the Dark Lord, catapulted him to the center of attention in the Slytherin common room, made him the very one they feared.

At fifteen, James Potter and his posse of friends dangled him upside down above the green quad of Hogwarts. When Lily Evans came, he slammed to the ground and felt his knees bleed, felt the red-hot shame curl up, steeling his resolve. He was surprised by the black anger that possessed him, all-consuming, every bit as frightening as his father's. Mudblood spilled from his lips out of habit, from those dreary days spent burrowing in the dark. He didn't mean it as an insult, didn't mean it anything other than a remark of anger, didn't mean it . . . didn't mean it. But when had intention to do with any of this? He watched Lily walk away. Then he turned to Potter and, snarling, hissed, Sectumsempra.

Potter healed. Severus never got the time to hurt. On starless nights, he tossed and turned in his bed, and sleep never came easy. There was, in the end, no rest for the wicked. Years ago, curled in the soft swirlings of Lily's hair, Severus had been young, he had been foolish. Haunted by Lily's hatred now, he no longer dared to give his heart away. There was a war brewing on the horizon. There was a group forming under the very roof of Dumbledore's castle, and Severus had found that brave, had found that impressive. When Lucius Malfoy took him by the wrist and asked him for the spell he had used on Potter that fateful day, he did not hesitate to give it away. Severus had never invented anything kind, but the ones he had invented were ferocious, and they had all killed with snapping jaws. Standing there in the dim light of an abandoned hallway, Malfoy stood awed as Severus slashed his whimpering rabbit apart. Days after, Severus found himself with a grotesque mark on his arm, and vaguely, he wondered if he should regret.

He gave the prophecy away because he had wanted so desperately to prove himself worthy. He never thought that the prophecy would be the one to condemn Lily to death. Lily. Lily . . . he had almost forgotten how she looked. On his knees, all he could see was the Dark Lord's acceptance, all he could see was home. When Bellatrix Lestrange came prancing into his room to declare that the Potters' Secret-Keeper had squealed—that was the worst day of his life.

In the end, he could not remember much of that day, except for the ruins of Godric's Hollow, for Lily's gauzy sleeve in the winter wind, for a baby that looked too much like its father. But God, he did not intend to kill Lily. He never intended to kill Potter, either. He did not intend . . . he did not intend. But when had intention to do with any of this? On his knees, all he could see was regret, all he could see was Dumbledore's white beard, that savior, that virtue. What will you give? Anything, anything.

When Severus was twelve, Lily had saved him from Potter, once. If he ever tugs your pigtails again, Sev, come tell me. I'll deck him, I will. He had smiled, teeth and all, and he'd said, Okay, General, but watch, I'll be a professor one day and I'll keep Potter's kid in detention seven days a row. Lily had tossed her head back then, snorting derisively. You, a professor? Professor Snape? I have trouble picturing it, and frankly, Sev, you'll be a crap teacher.

In the end, Severus did become a professor, and when Harry Potter entered the Great Hall, shoulders bowed, all he could see was James. In vindictive fury, he kept Harry Potter locked in his dungeon every detention, and found joy in smacking Weasley across the head. Harry Potter was young, reckless, arrogant, and Severus thought it funny that the weight of saving the world fell upon this boy's shoulders. But some days, sometimes, he would look up from his papers and find Lily's green eyes staring right back at him, and he would soften, would feel the wish to cry. Then Potter's face would twist in ugly hatred, and that face, Severus thought bitterly, belonged undoubtedly to James.

Those years passed by in a blur. He kept Potter from dying, because that was a debt unpaid, because that was what he owed Lily. Lily, Lily, Lily . . . He forced her from his head, because he could not afford to harbor that crippling regret. But then Dumbledore was dying, that cursed black hand, and oh, Lord, he was not ready for any of this.

You can't let him do this, Severus. He is too young to bear the burden. Only sixteen, Severus. But you, you have to. Severus had looked up antidote after antidote, and the grease in his hair deepened from the time he spent next to his cauldron. Too young. Did Dumbledore think he was old enough to kill? No, no, no, no. But he saw Malfoy's bleached hair, his trembling hand, his watery blue eyes, and Severus felt the realization crash into his mind, like the whip of a curse. Too young. Too young. Had he ever been that young?

The Killing Curse sat like an ulcer under his tongue days after he had uttered it. He spent the days by the Dark Lord, and often he dreamed of Dumbledore, sometimes of Lily, rarely of Harry. He did everything he could, and how he wished that was enough. Hermione Granger found the Horcruxes, and Severus had wondered if she knew that the last one was right next to her all along. They called Fred Weasley a hero, they called Neville Longbottom commander. Some called him coward, some called him follower, some called him scared, some called him dark. The only person who had known him for who he was had died at his hand, and what really could he do about that?

Severus flew from the Great Hall and went when the Dark Lord called. He had never seen Harry Potter wholly as Lily, had never seen the side that Harry Potter inherited from that little girl in Cokeworth. Now, parchment white and bleeding out from Nagini's bite, he saw Lily's eyes, and he saw Lily's kindness.

His vision turned to static. He took a breath, then whispered, Please, to the wind, listen to me.

"Always."