A/N: Written for a friend on Tumblr, who wanted a fic where Tesla covers the entire Sanctuary in mistletoe. 3

Helen was going to kill him.

Well, not kill him - shoot him a few times, perhaps. No, he would have enjoyed that too much.

After seeing the mistletoe hanging above the door to their room, she had expected it to show up in her office, though she hadn't been expecting three sprigs to be placed at perfectly equidistant points above the door, her desk, and the couch.

Predictably, Nikola had come sailing in that morning and seated himself on her desk with a wide smirk and a casual air. "Dearest Helen," he'd said sweetly. "What are you occupying that phenomenal brain of yours with today?"

"I had been occupying myself with next year's budget, but I have a sudden, unexplainable feeling that my attention may be required elsewhere for a few minutes."

There had been such a bright, mischievous sparkle in Nikola's eyes that Helen had rolled hers and leaned up, allowing him to kiss her. He was just so damned adorable when he looked like that. Frequently infuriating, but adorable.

It hadn't exactly been a surprise when he'd called Helen up to his lab later in the day and there had been yet another sprig over the entrance. For once, Nikola met her at the door instead of poking his head up from whatever he was working on some time after she'd walked in.

"I wonder how that got there," Helen had said dryly, nodding up.

"Hmm, quite the mystery," Nikola had replied, grinning. "You must have some kind of mistletoe elves infesting the place."

"Just one, I believe." Helen had given an exasperated sigh, but her lips twitched as she leaned in to kiss him.

She had always found Nikola's attachment to this particular holiday tradition more amusing than anything else. And (privately) she'd admit that she wouldn't mind catching him under the mistletoe on occasion.

Now, though, it was just getting ridiculous.

Throughout the rest of the day, Helen discovered mistletoe near the infirmary, the media room, the kitchen (she had no idea what it was doing there, Nikola never set foot in the big guy's kitchen unless he was making her tea), even the bloody abnormal levels – which apparently was causing quite a bit of hilarity among the residents.

And it was practically coating the halls, the front entrance, the library… Wherever Helen stepped, there was sure to be mistletoe overhead. Nikola must have been spending the entire day on this.

Right now, she was on her way outside to check the stability of one of the tunnels, walking through a corridor that he had covered every inch of in the stuff. Nikola whirled by, stopping to plant a delighted kiss on her cheek.

"Just wait until you see the roof," he said happily.

"You know, I'm quite sure I gave you useful things to do this week." She rolled her eyes and continued on her way.

"But this is so much less boring!" He trailed her, taking her hand and kissing that too. "And what worthier cause is there than showering my beloved Helen with affection?"

Helen would have expected a coat flip if he'd had any hands free, but he gave her a blinding and rather cheesy grin instead.

"Well," she said with heavy sarcasm, "'your beloved Helen' has a great deal of work to do today, so if you could take this – really, Nikola?" Nikola was kissing her hand every time she took a step.

"Mmm, your work ethic is so hot," he whispered against her fingers.

Helen stopped in her tracks, exhaling loudly. Nikola dropped her hand, apparently sensing she'd run out of patience.

"Too terrible? Yeah." He sighed, raising his hands in surrender and fixing her with a rather pathetic look. "Alright, I'll go back to the lab like a good little house elf."

"Dear lord." Helen rolled her eyes again. "You needn't act quite so mournful, Nikola. It's simply that I'm very busy today."

"Obviously. I mean, it can't be my kissing because I distinctly remember you telling me the other night that – "

"Yes, thank you Nikola," Helen said stiffly. "I recall it perfectly well."

"Well I'm glad, I'd have been a little insulted if you didn't." There was his brilliant, dimpled smile again; Helen felt her traitorous mouth give a twitch.

"You are enjoying this far too much," she informed him, starting to walk again. "And I do have much more important things to do than stopping to kiss you every five minutes."

"That long?" He looked up, grinning. "You're still under mistletoe, you know."

"Oh, for – " That was it. She was going to shut him up this instant. But she wasn't going to shoot him – she had something far more fitting in mind.

She turned to him with a wicked smile, then glanced over his head. "So are you."

"Well yeah, that was kinda the p- "

Helen seized his shoulders, pushing him against the wall and letting the force of her momentum carry her to his still open lips. Without hesitation, his arms came up to hold her tightly against him, his hands skimming over her back.

She twisted her hands through his hair, soft against her fingers, which caused him to give a little gasp against her mouth and melt even farther into her. Helen began to reconsider how much work she had to get done today.

In hindsight, it was doubtful that this was going to prove quite the point that Helen had intended it to at first, but she couldn't bring herself to give a damn. She pressed into him, kissing him until she had no breath left and had to pull away.

Nikola opened his eyes with a rather dizzy smile. "Helen," he murmured.

"Nikola."

"You're not under the mistletoe anymore."

It was true – they were pressed against the wall, outside the path of mistletoe hanging from the center of the ceiling.

"Not to worry," he continued, reaching into his coat. "As always, I have a brilliant solution." He pulled out a slightly bent sprig, still bright green and tied with a tiny red ribbon, and held it over her head.

"Just to be safe," he told her, his smile widening, and kissed her lightly on the nose.

She shook her head, chuckling.

"I know, I know, I'm ridiculous," he said, his eyes soft.

"You are." She kissed his cheek. "Just tell me one thing, Nikola."

"Anything, my dear."

"If I go outside, is there going to be mistletoe in the tunnels?" Helen raised her eyebrows at him.

His mouth opened, then closed. "…Maybe."