"T'was the night before Christmas, and all through the lab, all the creatures are stirring. It's really quite mad."

"Nice Walter." Peter plucked a piece of tinsel off his shoulder. "Isn't this getting a little out of hand?"

"Nonsense, Son," Walter answered, tottering at the top of a step ladder. "Seventeen years at St. Claire's. I have some catching up to do."

Peter really couldn't argue that; it'd been a long time since he'd celebrated the holidays himself. But, he did have his limits, and helping Walter hang twelve hundred blinking red and green LED lights was pushing them.

"Is Agent Dunham going to be back soon?" Walter leaned over to ask. The ladder started to the totter and Peter lunged to steady it.

"That's what she said when she called."

Walter grinned. "Excellent."

"Walter. What's going on?"

"Did you pick up the rum?" Walter tried to divert him. "Can't have eggnog without the rum. Do you think Olivia will join us for eggnog?"

"If you have rum, I think there's a pretty good chance of that." Walter gave him a look. The one that he saved for when he was about accuse Peter of being purposely being dense. "Fine. Yes. I think there's a chance Olivia will stay for a drink," Peter answered to placate him.

Walter hummed a few bars of a carol that Peter vaguely remembered his mother singing once upon a time. Peter plugged the last string of lights into the power bar and froze, waiting for something to short out. When nothing happened, he muttered a short prayer of thanks. There was a scraping sound behind him. He turned to see Walter dragging the step ladder over to the top of the stairs. It was a disaster waiting to happen.

"Walter!"

"Son, give me a hand here. I want maximum coverage. Olivia will be here soon."

Peter made a grab for the back of his lab coat, but Walter was too fast. "Walter, what's going on here?"

"Christmas," Walter answered. The corners of his mouth twitched, slightly, just enough that Peter knew Walter was up to something. He caught the way Walter's eyes dart up to the archway above the steps and that's when he saw it.

"It" being the largest sprig of mistletoe Peter had ever seen. He sighed.

"Really Walter? Olivia's not going to fall for that."

"Fall for what?" Of course that would be the exact moment Olivia'd walk through the door. She stopped beside Peter and looked up where he was staring.

Peter wanted to ask if it suddenly felt a little warm in the lab (twelve hundred lights must generate a bit of heat, right?), but just settle for clearing his throat.

"Olivia," Walter greeted her from the step ladder. "We were just talking about you."

Olivia bit back a smile that made Peter's stomach flip-flop. "Apparently," she said. "Is that mistletoe Walter?"

"It is. Sharp eyes you have my dear." Walter was practically vibrating.

"It's kind of hard to miss," Peter said. "It's the size of a beach ball. Where did you even find it Walter?"

"It's also hard to miss that you are standing under it," Walter added. "Right next to Agent Dunham. Come on, Son," he stage-whispered. "Don't leave a pretty girl just standing there."

And that's when Olivia blushed. Peter wanted to bang his head against the wall. Walter was setting them up, once again. Awkward silence followed.

It was broken by the sharp tap of heels on the concrete floor.

"Walter, the first batch is done, but I don't think-" Astrid trailed off mid-sentence while she took in the tableau in front of her. Peter wished he could disappear. Or at least change his last name and absolve any relationship with his father.

"Oh for crying out loud." Astrid dropped the sheet of cookies she was carrying onto the lab bench, rolled her eyes, and strode across the lab to where they were all standing. She placed her hands on Olivia's cheeks, planted her lips on Olivia's, and kissed her, fully. Seoundly. Olivia brought her own hand up to Astrid's shoulder and pulled her closer, deepening the kiss.

Peter reminded himself to pick his jaw up off the floor. Beside him, Walter let out a grunt and something that sounded a bit like "That's not how it was supposed to work."

Finally, Astrid broke the kiss, letting her fingers linger on Olivia's cheek, and turned to Walter. "You are needed in the kitchen. Your cookies are burning." She turned and strode back across the lab, snagging her cookie pan on the way past. Concerned for his shortbread, Walter followed.

Peter looked back at Olivia. She was watching his father's retreat with what he hoped was a touch of amusement. He took a step forward. "Listen, about Walter," he started to apologize, but she stopped him with her index finger to his lips. She looked up, and Peter followed her gaze.

The mistletoe bush still hung there above them like a disco ball.

Olivia grabbed the front of his shirt in her fist and pulled him to her. Her lips were still pink and swollen. Peter felt his breath catch. It was definitely getting warmer in here. She tightened her grip and held him close. And smiled.

"Merry Christmas?" she whispered and leaned in.

Yes, Peter thought when they broke for air, it definitely was.