All recognizable characters belong to J.K Rowling. Unfortunately, I am in no way affiliated with Mrs. Rowling.
Turning point
Black clouds covered the dark night sky, with lightning occasionally forking down from heaven, briefly illuminating the alleyways of the small village. One such flash revealed a young woman, who looked to be barely over twenty. She had bright red hair dull in the rain and a creamy complexion that was pale with weariness. Dark green cloth covered her round belly while blood dripped from a long gash on her left arm, onto a piece of willow wood that was clenched in her hands. If one looked carefully, he may see a small red phoenix perched on a classic staff adorning her dress. She was leaning heavily against the walls of an old abandoned warehouse that has seen better days clutching the fabric around her stomach. Her small frame shook incessantly with tremors, though it was a debate if it was due to pain, shock, weariness or most likely all of the above.
What happened? The woman tried to piece the jumble of images flashing through her mind together. She was seven month pregnant and thus assigned to one of the obscure small village that dotted the highlands of Scotland. It was supposed to be a safe assignment, but Death Eaters apparently decided to target this area. She had alerted the Order, when a battle broke out. She had held of Voldemort himself for a few seconds before the others arrived. The last thing she remembered clearly was getting hit by a blue light near the end of the battle, most likely a confundus charm then. It was a pretty common charm to use in a battle, requiring little power or finesse to disorientate, as compared to more powerful spells or the Unforgivables. The next was a hint of yellow light, before she became unconscious. It was surprising that that she even woke up. Spells that glowed yellow on the whole are nasty curses that affect the skeletal and muscular system, while red normally affects the nervous system. Someone must have put a shield up than, for a direct hit would have meant an inevitable messy death. The strange thing was that she could have sworn that only Death Eater was in the position to put up an effective shield that had saved her life. Oh well, she was probably still Confounded.
The rain had finally slowed to a drizzle, and the woman took careful stock of herself. A gash, on the arm, slight pain in the ribs and magical exhaustion – altogether it wasn't too bad, considering who she had been dueling against. She had somehow gotten separated from the main fight and gotten thrown into the alleyway. With her magical exhaustion, there was no way she could contact anyone for help. It seemed that both the Death Eaters and the Order had left the ghost town.
She could feel the contractions getting more and more painful and intense. She was too weak. Normally magic would tell her hours in advance of a birth and incidentally numb some of the pain. Yet due to her exhaustion, she was going to experience the full pain of a muggle birth. Just as she was about to give up, a shadow appeared in the mouth of the alley. Could it be one of the Order? Glancing up, to her horror it was a man dressed in black Death Eater robes wearing a silver skull mask. She couldn't help but feel despair washing over her. Was this her fate, to die along in a ditch with her unborn baby, murdered by a monster?
She closed her eyes, waiting for the end. It never came. Then the black clad man spoke, a single word, a voice that haunts her memory, "Lily."
Severus Snape was not a good man. Anyone who know him can testify that he was an angry man, cruel and unyielding, without a hint of human emotions other than hatred and rage. A man so cold he was even feared among the ranks of the Dark Lord's Death Eaters. A single look from his black eyes seems to pierce into the soul, exposing all of one's weakness and petty fears. He had joined the Dark Lord right out of school, and had become one of his most trusted servants. He had quickly outranked Lucius Malfoy who had recruited him. Unlike most Death Eaters, he was valued by the Dark Lord not due to the count of bodies he left behind, but because of his talent in potions. The Dark Lord had sponsored his apprenticeship to one of the foremost Potion Masters in Europe and the world. As payment, Severus had gained his mastery in merely two years instead of the usual seven, gaining him the reputation as the youngest Potions Master in almost a thousand years.
Being the Potions Master for the Dark Lord, Severus rarely joined in the more gruesome activities the lesser of his Lord's servants indulge in. It was said that he was incapable of feelings, not even the twisted glee of harming another. It was thus with detachment that he joined the attack on the nameless village on his Lord's orders. He had expected to stay on the sidelines, too valuable to risk injury from fighting, waiting to patch up his fellow Death Eaters. Thus the sight of a pregnant Lily Evans – no, Potter, he corrected himself – fighting the Dark Lord, shook him to the core, stirring memories of happier times. Out of impulse, something that he hadn't done since he was a fifth year at Hogwarts, he had raised a shield when he saw a Cariosus, a rottingcurse, shooting at his old friend. His actions unsettled him greatly. He had gotten over his crush on her already, he was certain of that. So why did he do something so uncharacteristic? For the sake of past friendship?
As he wandered the abandoned village after the fighting was done, he noticed a trail of blood leading to an alleyway. Morbid curiosity drew him to the alley as he wondered if the person is still alive. As a Potions Master, he was trained in healing to a certain extent, having even worked at a hospital for some time during his apprenticeship. As it is his duty to patch up his fellow Death Eaters, duty compelled him to enter the alley on the off chance that is was an injured fellow down there.
"Se – Snape?" the woman, Lily gasped. Green and obsidian eyes met for the first time in years as they stared at each other. Then, as if in slow motion, he reached up and removed the silver mask hiding his face. For some reason, hearing Lily calling him by his last name sent a pang through his chest.
"Why?" Lily asked in a pained voice. Severus didn't bother asking her what she meant. There was too much unsettled history, too much pain. Why did he betray her friendship? Why did he join the Dark Lord? Why did he save her tonight, as she finally realized? Instead of answering, he reached into his robes and drew his wand. For what answers could there be that would satisfy all those questions?
Lily watched in apprehension as Severus raised his wand, not having inkling about his intentions despite the fact that she used to be able to read him like an open book. Despite the seriousness of the situation, a hint of wistfulness entered her heart. The feeling intensified as her childhood friend conjured a bed, levitated her onto it and began casting diagnosis and healing spells on her with sure, practiced movements. The cut on her arm healed, along with the various cuts and bruises acquired over the long night.
Severus's movements are methodical and habitual as he took care of Lily's injuries. Beneath the calm surface though, his thoughts are churning. What on earth are you doing, healing the enemy? Part of his mind screamed at him. If any Death Eater, or God forbid, the Dark Lord, finds out, you'll be branded a traitor and death would be a welcome! A smaller, but no less strong part whispered back, But is Lily an enemy? She certainly never hurt you, unlike some… She was your friend, the only person who understood you when you were in pain.
"I've done all I can. You should check in with St. Mungo. The external injuries are taken care of, but I don't have the potions and equipment to do a thorough check. As for the baby…" Severus said softly, blushing as he trailed off.
At that moment, a convulsion rippled through Lily. "Shit! What should I do?" Severus panicked. He had never delivered a baby before! Lily groaned as the pain hit her. Why did this have to happen now? I'm not due till another three weeks. It must be the stress of the battle.
The groan of pain brought Severus out of his stupor. His healer training kicked in as he positioned Lily into a suitable position. Fortunately for them both, it was an easy birth. The baby was out within five minutes. As Severus cut the umbilical cord and got rid of the blood, Lily opened her eyes. "Thank you, Sev."
His childhood name on Lily's lips made Severus' heart leap. "Congratulation, it's a boy," he whispered the traditional well wishes. The baby looked health and utterly adorable. It was at this moment that Severus' mind finally calmed. He had come to a decision. Lily smiled. "Will you care of him as your own if I am ever unable?" she asked. His heart stopped. "Yes," he replied unaware as old and ancient magic surged through the air, cementing the vow made in the cool autumn air.