He had to tell her. His arm burned. Excitement simmered in the pit of his stomach. Her sister answered the door.
"Is Lily here?"
Petunia looked at him with distaste, eyes travelling over his baggy jacket and faded robes.
"Why are you here? What on earth are you wearing?"
His hand itched, involuntarily moving towards his wand, before he stopped himself. Petunia's eyes widened. Stupid little muggle. She must think he was carrying a knife or some other crude form of weaponry used by the gangs around his neighbourhood. As if they'd have any hope if he ever decided they were worth wasting a spell upon.
"Is Lily here?"
Petunia inched backwards from the doorway, looking scared.
"No," despite her fear, a note of spite crept into her voice as she continued, "she's out with that hooligan boyfriend of hers. You know, the one with rich parents?"
Anger coiled around his spine, and his hand twitched again. All it would take was one little word, and he'd never have to hear the incessant grating of her voice again. The only thing that stopped him was that Lily would be upset. She loved her sister and parents, despite the fact that they didn't possess a scrap of magical ability between them.
It wasn't her fault, Lily's irrational love for muggles. She had been raised by them, indoctrinated in their pathetic beliefs. By the time she got to Hogwarts, the damage their pitiful morals and customs had done to her brilliant mind had been impossible to reverse. Potter had no such excuse. His entire family were blood traitors and half breeds, and extermination was the only way the wizarding world would ever be free of their taint. The stars winked down at him, seeming to share his conviction, his new sense of purpose.
He was halfway home before he heard footsteps behind him.
Turning, he saw Lily hurrying to catch up with him, red hair loose and drifting around her face as she jogged to catch up with him. Stopping, she tucked a few strands behind her ear, tension apparent in the set of her shoulders. She kicked the pavement uneasily, avoiding eye contact. He felt like the wind had been knocked out of him.
"Tuney said you called for me whilst I was out. Apparently you were pretty worked up,"
Now she was here, he didn't know what to say. They hadn't spoken in nearly two years and it was as though he had lost the knack of it. The sense of righteousness he had carried around with him for a week now seemed to have evaporated, replaced by something suspiciously like anxiety. But he didn't take a deep breath as he pulled back his left sleeve, didn't do anything to show that he was nervous. Somewhere in his head a voice was shouting, telling him this could only end badly, but he ignored it. She would see that what he had done was right. She had to.
Through the haze of pain as the darkness crawled under his skin, Snape had thought the image forming there was the most beautiful thing he had ever seen. It was a symbol of his allegiance, a sign that he was pure, that he belonged.
Lily flinched, her pale face turning even whiter as she stared at the tattoo. The shadow snake seemed to move under the flickering illumination of the lampposts lining the street, the skull's leer becoming even more menacing. When she spoke, he had to strain to hear her.
"Merlin's beard Sev, what have you done?"
No. This was all wrong. She wasn't supposed to react like this.
"What have I done? What I was always meant to do Lily. Can't you see, He is the only hope we have! This existence, it's pathetic! We were meant to rule, not hide in the shadows!"
Lily was shaking her head slowly.
"They're evil Sev, He's evil,"
"How dare you! You know nothing of the Dark Lord, nothing!"
She reached out for him, her voice low and placating.
"Sev..." he jerked his arm away from her hand.
"Don't touch me! Don't touch me you filthy little mudblood!" All wrong, it was all wrong.
Lily took a step backwards, lip trembling, and for a moment it looked like she was going to cry. But then her emerald eyes flashed with anger.
"You think you're so cool don't you? You and all your little Death Eater friends, walking around in robes, refusing to look like normal people because that's what you think this is about! He doesn't care about you and your beliefs Sev, all he wants is death. You look like a freak, and soon you'll be a murderer!"
He reached out and grabbed a fistful of her cropped t-shirt, the fabric ripping as she twisted away from him.
"At least I don't walk around dressed like a common muggle slut!" he roared, "I've seen the way he looks at you, your blood traitor boyfriend and his stupid little crew, like you're meat. His whole family are traitorous rot and so is he,"
"And your family history's so noble isn't it Snivelly? It certainly seems that way when your father staggers down the road at 2 o'clock in morning, stinking of whiskey!"
"Don't you dare talk about my father like that! You're not fit to lick his boots!"
"Neither's your mother if the black eye she's had for the last month is any indication!"
With a wordless scream of rage, he pulled his wand from the folds of his robe and pointed it directly at her heart, unforgivable words dying on his lips as he noticed that she had made no move to defend herself.
They fell silent, staring at each other, both breathing heavily. A single tear rolled down Lily's cheek.
"Go on then Sev, curse me. One less mudblood. Isn't that what your master wants?"
He didn't move, tremors running through his wand arm as she stood opposite him, her defiant posture belying the rivulets running down her face. He didn't know how long they stayed standing like that before, with a dismissive flick of her head, she turned and walked away.
She was half way down the street before he found his voice again.
"Don't you dare walk away from me you filthy little whore! I'm not finished with you!" His voice cracked, and Snape's next words were spoken in a whisper.
"Please come back,"
She didn't turn around.