A/N: Hello! I'm sorry for abandoning this story! I honestly can't remember if it was a few nasty PM's (long forgotten) or if I had some writer's block (gone, if it ever was.) Really, I kind of forgot about it, but I got some new follows and was reminded that I needed to finish this. Diving back in with a short chapter…

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Castle woke slowly, blinking in the late morning light. He reached toward Beckett's side of the bed even though he knew she wouldn't be there. The light meant the sun had been up for a while and he wasn't surprised to feel only cool sheets beside him. Still, he felt good. He stretched in a lazy Saturday morning kind of way, arms up over his head to press his palms against the headboard, back arching, toes pointing. When he relaxed, he sank back into the haze of semi-sleep and closed his eyes.

In the stillness he flexed his hand, the fingers curling one after the other until he formed a fist and clenched. No pain. He relaxed again and sat up, yawning. He felt a passing wave of grumpiness that Beckett hadn't woken him when she left. Then he grinned, because it didn't matter. Today he was going back to the precinct after a few days off. It was a good day.

It was with a child-like sort of glee that he purchased Beckett's coffee, over-tipping the barista and nearly dropping both drinks in his enthusiasm. A quick text exchange with his girl (as he seemed to be thinking of her lately, though he loathed the thought of what she'd think about that) and he was headed to the crime scene. When he arrived he could barely contain himself. He'd only missed a few days, at Beckett's insistence, but it was so good to be back. He grinned at each beat cop he saw, bumped fists with a few detectives, and finally caught sight of his girl (he had to stop that) and the boys. And Lanie, who was speaking when he arrived.

Castle walked up just in time to hear her call Esposito "baby." Whatever efforts he'd made to contain his delight were tossed aside with abandon.

"Baby?" He repeated with a theatrically raised eyebrow as he stepped in next to Beckett. "Cute, but isn't that a little casual for-"

"Oh, uh-uh, Castle," Lanie retorted. She held up a gloved finger to stop him. "Do not even get me started on you two, okay? You think we don't notice the looks and the long lunches and how sometimes one of your hands is hiding between her-"

"Lanie!" Beckett hissed, the one ear her hair was tucked behind an angry red.

Lanie eyed them both, and gestured. "How close you stand together…"

"Okay!" Castle held up his hands. "I don't even remember what you said. Were you saying something about the body?"

Lanie glared again, and then smiled and patted him on the cheek. "Welcome back, Castle."

Back in the car and headed toward the precinct, Beckett took a sip of her latte and hummed. Castle smiled and leaned halfway across the distance between them.

"It's so good to be back. Here. With you."

"Mmm, it's good to have great coffee again."

Castle puffed out a breath and sat back, crossing his arms until Beckett gave in and took one of his hands in hers. She didn't look over, didn't apologize for being glib, but he could read the true sentiment in her smile when she laced their fingers together. He squeezed lightly; silent acceptance of her silent peace offering. He leaned back in the seat and he was happy.

Later that night, Castle wouldn't be able to put his finger on when the day started to go wrong. There was no sudden chilling reveal of bad news, no sharp words that set people on edge. But their happiness was like an ice cube left out on the kitchen counter, losing its shape and dripping away off the edge of their day. In retrospect, it might have been some of the first information that came in, that their leads were pulling them into Washington Heights.

"Washington Heights is a shady place that time of night," Beckett muttered, pacing away from their murder board with a distracted pull of her fingers through her hair.

Just the mention of the place and Castle could feel a pull near his spine, his head suddenly too heavy and his shoulders working to carry the extra strain. And Beckett's smile fell away and stayed gone, melancholy present in the cross of her arms and the list in her stance. There were too many sighs, and not just from her. The whole team was trudging through dreary work. The case felt heavy and somber. Castle, who had been so happy to be back working with them, felt useless without the opportunity for his usual quips and silly theories.

There was something wrong, and none of them could put their fingers on it right away. The evidence was dark and murky. A stripped cab, Syrian suspects with diplomatic immunity, Washington Heights, a mysterious dolly. And Beckett was drifting away, preoccupied, internal, working too hard to focus.

At the precinct, Castle made her a fresh mug of coffee, but couldn't read the flick of her eyes when she accepted it from him. Unsure of what she needed, Castle moved back to stare at the evidence. To do something helpful, to think of something new. Finally, Castle sat up straight in his chair.

"It's an address!" He stood up, looking around for someone to tell. While he'd been thinking through the evidence, the team had wandered into the breakroom, so he scrambled over to them, ignoring the chair he knocked over on the way. "It's an address!" he repeated, holding onto the doorframe and swinging his head into the room. "The string of numbers, look…"

He gestured, and they followed him sluggishly back to the board. "This part of the number is an address and if you look it up it's a storage place." Finally, the others seemed to shed their misery as a group, a new lead offering the solace of action.

"It's a storage unit," Beckett agreed, eyes narrowing as they closed in on the clue. For the first time in hours she made real eye contact with him and even managed a little grin.

At the storage facility, she even gave him a soft eye roll at his expected Indiana Jones joke. After she opened the door and they waited for their eyes to adjust to the dark, Castle allowed himself a small moment of intimacy, and he pulled a few chords of her hair out from where they'd gotten trapped when she hastily threw her jacket on. After smoothing her hair in place, he squeezed the tense muscle where her shoulder met her neck.

"You okay?" He asked softly, his nose almost brushing against the top of her head.

The corner of Beckett's mouth lifted slightly, though it was more grimace than smile. Her eyes flicked up to him, still darting, and then back to the gaping maw of the storage unit before them. "Let's do this first, okay?"

Before Castle could even begin to panic about all of the potential implications of that statement, Beckett was stepping inside. "It's empty," she muttered, her flashlight sweeping the space until it illuminated a single crate at the back of the room.

Despite his attention still being mostly on his partner's mood, Castle managed to quip, "Well, the Arc of the Covenant was in a crate."

They walked up together, and Castle lifted the lid while Beckett held her flashlight steady. What they found had Castle letting out a dark, low laugh. "Woah," he murmured. It was rows and rows of plastic explosives, neatly packaged and ready to blow up something big.

"So-"

Castle never got to voice his thoughts. An alarm he'd never heard before went off at Beckett's hip, and he could see the red illumination of a lighted device there.

His head tilted curiously, but Beckett spoke before he could. "Castle, get out!"

"What?"

This time her voice was strained and left no time for questions. "Get out! Get out now!"

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A/N2: Thanks for reading. Man, I loved Setup.