A/N: Part one of what I believe shall be five. Whoo, Chuck and Blair, how ten months ago.

The first time Blair Waldorf kissed Chuck Bass, Nate could see them through the doorway, standing in the hallway waiting in line to use the bathroom. New Year's eve, his least favorite of Serena's favorite holidays, returned full force, and she'd thrown the party. Serena always threw the party, or so it seemed. Were he completely honest with himself, Nate would realize that he didn't even like parties all that much, but he really liked Serena, and she always seemed to be at parties. It was almost worth it. But not this time, at two am in the hallway waiting in line to use the bathroom. Blair Waldorf kissed Chuck Bass as Nate watched the scene unfold.

Perched on the corner of Serena's messy, never-made canopy bed, Blair kicked her heels against the side of the side of the mattress and sipped delicately at her mixed drink, hair unkempt and crossing every which way over her bare back. "How come you never hit on me?" he heard her ask, her high voice slurring slightly at the end. "Am I seriously that hideous?"

Nate spotted Chuck, half-visible, splayed among Serena's pillows, and clearly too plastered to get out of bed. "Blair Waldorf," he said, hair pushed up against the headboard, Easter egg khakis wrinkled and pleatless. "Blair Waldorf. You're untouchable." Blair snorted.

"Untouchable? Seriously, Chuck?" Chuck Bass nodded, gazing at the ceiling. "What does that mean, untouchable? Too fat? Too ugly? Too anal-retentive?"

"You're Nate's. No one else can have you." Nate could feel his stomach drop at the mention of his name. They seemed oddly intimate, his girlfriend and his best friend. Like he shouldn't be watching this. Like he shouldn't be there, waiting for the bathroom in the hallway of Serena's apartment at two am on New Years. Chuck swung his legs over next to Blair's and leaned in against the back of her neck. "You're beautiful."

"What?" Blair asked. "That's the best you can do?" She gathered her hair with her hands and released it again. A silk spaghetti strap slipped off of her shoulder and down her arm. Chuck ran his hand through his own hair, leaving it sticking up and over in unnatural ways.

"It's true, though," he said, and pushed the strap back over her shoulder. Blair shivered. "You're ethereal."

"You're drunk," Blair said, and giggled. "I bet you wouldn't touch me with a ten foot pole." Chuck sat up and very deliberately placed his hand on top of hers.

"Where's the pole?" he asked. Blair giggled again.

"I'm going to kiss you," she said. "Do you think the world will explode?" Chuck coughed.

"You're going to kiss me?" he repeated, voice cracking. Blair crossed her legs, leaned in, and kissed him on the side of the mouth. Chuck coughed again. "The untouchable Blair Waldorf just kissed me," he said, slowly, and he wrapped his arms around her waist and tugged her down onto the messy bed besides him. Blair giggled, cheeks stained a dark pink. And then Chuck kissed her, fingers tangled, fabric bunching at the small of her back, noses smashing together. They kissed each other.

And then it was over, legs pressing against legs, neither silk strap on Blair's shoulder, Chuck licking his lips as neither party pulled away. Nate's fingertips began to tingle, in the hallway, waiting for the bathroom.

"Maybe." Blair said, voice wavering, high and shrill. "Maybe this is a little bit too much." She let out a small laugh. "Maybe I'm a little bit untouchable."

"So where's the apocalypse then?" Chuck asked, and he ran his fingertips along Blair's thigh.

Nate's own empty-stomach spirits threatened their way back up. The bathroom lock behind him clicked open, a drunken Hazel stumbling past, and Nate whirled around to use it, kneeling on the floor over the toilet and holding his breath in hopes he wouldn't have to accommodate his twisting stomach. And he didn't. Nate would always remember that he didn't throw up that night—the only New Years since the age of eleven for which the contents of his intestines stayed put.

The entire thing left him unsettled, and oddly paranoid. Like it rendered him useless, the connecting thread between Chuck and Blair, no longer necessary and cast aside at whim. Like they'd wake up the next morning and never bother speaking to him again.

And they didn't—speak to him, that is—the next morning. Until midway through breakfast, the three of them crowded around a leftover fruit plate on the counter. Nate chewed an unusually large grape carefully, running his tongue along the seed.

"God," Blair announced, much more loudly than the circumstances really required, "I am so hung-over." Chuck stabbed a pineapple slice violently with his fork. "I seriously don't remember anything!" Blair continued, her shrill voice echoing slightly in Serena's cavernous kitchen. Chuck's hand flew to the back of his neck, and stayed there.

"I don't remember anything either," Chuck said, clearing his throat. He looked up at Blair pointedly and her face flushed as she suddenly became interested in picking the sprinkles one by one off of her doughnut.

"I have a headache," she added, her bare left foot shaking against Nate's knee. Nate felt jumpy himself, the adrenaline receptors in his brain screaming at him to Just Do Something Already!

"You know," he said, and his voice cracked as both Chuck and Blair's heads swivel around, like they'd actually forgotten he was standing right there beside them. Nate coughed. "You know, it's like you guys could have really done pretty much anything last night," he blurted out before he could stop himself. His heart jumped—bang, up to his throat, and Nate coughed again. "It's like, no one would ever know," he clarified, tugging on his earlobe.

Chuck's head shot up to stare at him. Blair very suddenly stopped moving, her left foot freezing against the skin on his leg. Nate could feel his face flush as he stared into his glass of milk. He was used to this feeling, the burning oh-why-did-I-have-to-open-my-big-retarded-mouth of embarrassment. Nate hated that feeling.

The weird thing was, he didn't think he was even angry. He really wasn't. He knew he should have been. Somewhere in the back of his mind he felt betrayed maybe, or, no, that wasn't quite right. Abandoned. Left out. But Nate wasn't angry. He just felt kind of weird about it, a bad taste in the back of his throat he couldn't quite shake. Nate wasn't supposed to know about this. The world didn't explode. The apocalypse didn't come, not this time, not for this crime. Except, Nate kind of wished it would, for once.

A/N: Yay, Nate!angst. It's the best kind, really, and you know it :)