Aiden moved about the lab quietly, almost tiptoeing as she walked from one empty room to another. There were other people there, of course, but they were few and far between on Christmas Eve. So she roamed from room to room, taking her time and thoroughly going over the evidence from her most recent case with no distractions.

She was bent over peering into a microscope when Don arrived.

"Hey," he called as he walked into the room.

She lifted her eyes from the scope and smiled. "Hey."

Some very naughty thoughts flitted through his mind at the sight of her, but steeled himself against them. They had an agreement to be professional at work, and he was determined to stick to it.

"I spent the entire evening running down the alibi Walker gave us," he told her in an even voice. "Turns out, he wasn't where he said he was."

"No!" Aiden replied with mock surprise. Then laughing, she continued, "Where was he?"

Don smiled broadly, knowing they had just broken the case open. "He was in the south Bronx fencin' a stolen necklace."

"Did it happen to be a pink enamel heart with a diamond in it?" she asked, describing the victim's piece of jewelry.

"Bingo," he grinned.

"That's enough for a warrant…and when I get his DNA, I can compare it to the blood stain I found on the victim's jacket."

"We got him."

They shared a victorious smile for a moment before Don finally realized that they were almost completely alone. "Where is everybody? It's like a ghost town in here."

"They're all on vacation," she replied, "or with their families. We had to keep a crew on 'cause crimes are still committed this time of year and this time of night, of course, but there's only a few of us."

"How come you're working?"

She shrugged. "I wanted to go over this case again by myself…and I didn't have any plans tonight, so…"

He blushed a little at the last part. "I'm sorry, Aid…I tried to get tonight off…"

She moved toward him, reaching out and touching his cheek softly. "It's okay, you don't have to explain it to me. I know how this job is."

He took her hand in his and kissed it gently, stepping closer to her. "You still want me to go to your grandmother's with you tomorrow?"

"Of course I do. It wouldn't be Christmas without going to my grandmother's." She smiled impishly and squeezed his hand. "And I'm gonna have fun introducing you to the Burn family."

He winced slightly as she said it, but was relieved she wasn't angry with him. "As long as your brothers don't try and start anything…"

She took another step closer to him, her free hand traveling slowly up his chest. "Don't worry…I'll protect you."

He laughed. "But who's gonna protect me from you?"

"You're on your own there," she purred.

A dopey grin spread across his face as he slipped his arms around her, every thought of their professionalism pact having fled his brain. "I'm looking forward to that."

Her fingers slid through his hair and she leaned up, closing her eyes and parting her lips, but he stopped her just before her mouth reached his.

"Wait," he told her, fumbling through his pockets. "I brought you something." He fumbled another minute before he found a green, leafy branch and pulled it triumphantly from his coat.

"What's that?" Aiden asked.

The dopey smile returned. "Mistletoe."

She laughed, reaching for him again. "That's very romantic, Detective Flack."

He held the plant over their heads and pulled her close to him, leaning down to finish what she had begun. "You bring it out in me, Detective Burn."

He kissed her, softly at first but with growing intensity. After several minutes, the two reluctantly separated, breathless and dizzy.

Don leaned his forehead against hers and smiled happily. "Merry Christmas, Aid."

She returned his smile sweetly. "Merry Christmas, Donny."