Disclaimer: I own nothing. JKR owns Harry Potter, Regina Spektor owns the title song, and I'm a poor college student so please don't sue me. Enjoy!
Lily Evans strode up the street, tugging her muffler tighter around her mouth to shield against inhaling the sharp, cold air, and the resultant clouds that issued when she exhaled, like fragile ghosts of dragon's fire. There was no need to check the house numbers as she passed; it was the one on the very end with the oddly peaked roof and slightly discolored paint. She ascended the front stairs gingerly, careful to avoid the patch of rotten wood on the second step, and knocked timidly on the narrow door. It opened to reveal a slight boy with unkempt black hair, who grinned upon seeing her.
"Happy Christmas, Sev!" Lily said, her cold-flushed cheeks spreading into a smile to match his. Severus Snape darted a quick glance over his shoulder, and then stepped outside to join her, closing the door behind him.
"It's Boxing Day," he said dryly.
"I know that, silly. I couldn't get away yesterday; you know how Mum gets about Christmas. But I'm here now, and I've brought you a lovely present, so don't be cross with me."
Severus flicked his matted hair out of his eyes. "I couldn't be cross with you if I tried. You're so disgustingly delightful; I'll bet you eat Cheering Charms for breakfast."
"Severus!" Lily gave him a playful shove which he accepted with a small smile that was simultaneously bashful and sly. It flashed across his face for an instant, before he returned to his usual neutral, sullen expression.
"You didn't have to get me anything, you know. I haven't got anything for you."
"Well, that's no matter! It's much nicer to give than receive, Mum always says."
"Oh, I see. As usual, I get the short end of the stick."
Lily snorted. "You do realize that you are completely impossible be nice to?" Although she said it jokingly, she felt badly the moment the words left her mouth.
"Well, that certainly explains Potter and his ghastly friends, doesn't it?" Snape sat down on the top step and Lily followed suit.
"Oh, nothing could explain Potter… unless his mother dropped him on his head as an infant." Lily made a small face, eager to steer the conversation away from such an unpleasant topic, which was one of his favorites but which she preferred to avoid. "Let's not talk about him, it's holidays and we don't have to see him until Monday, which is something all of its own to celebrate. Now, open your present." Lily pulled a small parcel from her jacket, wrapped in brown paper with a small sprig of holly stuck bravely on top, and handed it to Severus. He undid the twine, ignoring the holly, and folded back the paper to reveal a good-sized clump of deep green, arrow-shaped leaves.
"Aristolochia rotunda?" He guessed, prodding the expertly dried leaves with a long, spindly finger.
"Yes, or what everyone else calls smearwort. You've been scribbling in that Potions book of yours all year about medicinal potions, I figured it was about time you started making them, eh?" Severus weighed the packet experimentally in his hand, a curious expression on his face. "I know it doesn't look like much," Lily continued hurriedly. "But the apothecary said a little goes a long way with this stuff and—"
"It's perfect, Lily. I've got a new recipe almost all figured out to counteract the burns from the Combuere Jinx; I've been itching to try it."
"I know," Lily said with a smile. She glanced down the street. The sun was sinking into the horizon, its pinkish glow fighting the grey smog for visibility. "I'd best be getting home, I've got to help Mum put dinner on."
Severus stood up immediately. "Let me walk you home?"
"Well, all right, I suppose. If you want to, it's awfully cold."
"Really? I hadn't noticed," he said sarcastically.
"You—" Lily shook her head and tried to give him a disapproving look. Severus extended a hand and pulled her up to her feet. She came up with a small jump, careful not to slip on the film of ice coating the steps and the street, and brushed off the thin blanket of snow that had fallen over her blue jacket. "Come on then, let's go."