Author Note – spoilers for season eight episodes Informed, Infiltration, and Underbelly. Please forgive me, I found it hard to write Casey, for me she's as difficult as Munch, so I kept her to a minimum in this one shot. Enjoy.

Disclaimer – not mine, just borrowing for fun.

Don't Tell Him

The bar is crowded and louder than she needs right now. It's been a long day, a longer month, and all she wants to do is crawl into her bed and sleep for ten hours. The power nap she had on the red eye wasn't nearly enough, her adrenaline kept her going through the day. A little cajoling from Casey means she has a few hours to go before she can indulge in the welcoming comfort of her own mattress and comforter. She never appreciated them enough before having to camp out in Oregon for over a month. A guy stumbles and belches as he passes the end of the booth, looking rougher than he should for a weeknight trip to a bar. He wears suit pants and a dress suit and she figures he must have lost the tie and jacket hours ago, long before the alcohol kicked in. He casts a bleary grin in her direction and she barely refrains from wrinkling her nose as he mumbles what she assumes is an apology. She nods politely in response, hoping he doesn't take it as an invitation to slide in next to her as she waits for Casey to return from the bar. All she wants to do is indulge Casey for a celebratory drink and go home, she has no interest in fending off any advances.

Fortunately, another guy, only slightly less inebriated, hooks an arm around the guys' neck and guides him back to their rowdy group of friends. She blows air out through pursed lips and cranes her neck to try to see Casey at the bar, eyes bulging when she sees the ADA struggling with two bottles and two shots. The blonde concentrates on crossing the floor, others dodging her as she makes it over the booth without smashing or spilling anything.

"I thought you said onedrink," Olivia comments as she takes a bottle of beer when they're safely deposited on to the table. Casey slides one of the shot glasses in her direction before taking her place on the bench opposite.

"One drink isn't enough for the week I've had," the blonde responds dryly before taking a big gulp from her bottle. She takes a quick breath then takes another, smaller sip before placing it on the table. Her eyes close as she expels a sigh of pleasure.

"Rough week?" Olivia questions with a smirk. Casey's sigh turns into a serene smile, bobbing her head in agreement as her eyes slowly open and focus on the hard to find detective.

"You made it harder," Casey replies unapologetically. Olivia wrinkles her nose.

"I couldn't help it," she defends weakly. "Besides I asked the feds to tell Cragen but I guess they didn't think it was necessary."

Casey isn't fazed by the explanation, almost like she was expecting it. "Always the same with them," she sighs. Pause. "People missed you."

People. The word is non-specific and all encompassing. Her tone isn't. Casey fixes her with an unwavering yet not completely unsympathetic stare.

"Right," Olivia replies doubtfully, fiddling with the label on her bottle.

There's nothing she can say to defend how she left. Timing has screwed her and any explanation. Less than a month after her return from Computer Crimes she abruptly left again. People would make the connection and assume the worst. No one would believe she didn't intend to leave, all she wanted was to help her victim. Dana knew how to play on her emotions, 'For Haley' she said. They would think it was to do with the tension between her and Elliot.

Elliot would think it was to do with the tension.

She didn't leave because of him but he would think she did. And she made it worse by hanging up on him the other day. She was already on edge and the sound of his deep rumbling 'Hello' startled her. She regrets losing her nerve, she's missed him. Thinking back now she can remember the almost playful, welcoming tone he used she missed in her spur of the moment reaction. Elliot's going to be pissed when he finds out she's back in the city.

"How are they?"

A knot forms in the centre of Casey's forehead. Olivia knows she wanted her to be more specific but she won't and can't give her the satisfaction.

"No one knew if you were coming back. Cragen had to bring someone in to help with the case load."

Olivia snaps her head up. That hurts and Casey knows it. She wonders her motive for the low blow. They're friends but it's a different dynamic from her friendship with Alex. Perhaps that why Olivia was wary when Casey was assigned to them, brash and determined to make her mark. She was hands on and didn't allow them the freedom Alex had. It took her time to learn to trust them. They exchange pleasantries but rarely go out after work unless it's the entire team. On occasion they've reluctantly confided in each other in the past because their personal experiences hindered the progression of their cases, offering support when needed without becoming too close.

"How are they settling in?" She hates how needy this sounds. She doesn't want to think about being replaced. She could understand it with because they didn't know when or if she was coming back but she hoped it would be an option.

"Like I said, people miss you." Her jovial assurance does little to reassure her, in fact it extinguishes any hope she had to return to her old unit. Casey waits a beat for Olivia to respond before lifting her bottle to her mouth to take another satisfying sip from it. She replaces it on the table. "So are you all done with the FBI?"

"For now. It was a waste of time, they had me with the wrong group the whole time," Olivia replies with a self-depreciating laugh.

"You're kidding?" Casey questions with a chuckle of her own.

"Nope," Olivia shakes her head.

She says nothing of the young girl who killed her abuser to save his next potential victim. Her last days in Oregon only served to confirm what she already knew. She missed the cases as much as the team. She didn't like the distance between her and the victims, she didn't feel like she was supporting them. She doesn't feel that Eco-Terrorist cases are less important than Special Victim cases but she needed to be back where she belonged. Like Elliot said before she returned from Computer Crimes, it's in her blood. She reconnects with Casey's gaze.

"What happened with Chelsea?"

Casey grimaces and leans in. Her forearms rest on the tables' edge. Her voice drops, cautious to keep this between them. "She wasn't coping with the setbacks," Casey says. She shakes her head. From the little information Olivia knows, from what she knows about Casey, she knows Casey feels partly responsible. She also knows Casey did all she could to help Chelsea in her stead. "I was worried what she would do if you never showed up."

"If I had known, I would have-"

"It's not your fault. I didn't know you were needed, Elliot made the arrest. I should've checked," Casey cuts her off. Her blue eyes steady on her face. She looks like she wants to say something else but thinks better of it. Casey isn't known for holding back. "He helped to look for you, he was worried about you."

She meets the news with silence, not really sure how to respond. It's far from the anger and sulking behaviour she's envisioned for the past month. She's surprised Casey let it slip, she isn't one to meddle.

"Do me a favour? Don't tell him I was here," Olivia says surprising herself more than anyone. There's a finality to her tone she knows Casey will argue with. "Not yet anyway."

"What do you want me to say?"

"I don't know, tell him I only had time to testify and I had to get back to my assignment, don't bring it up unless he does."

"Olivia," Casey protests shaking her head. Olivia knows it's unfair to ask her to get in the middle of this.

"He deserves to hear it from me, no one else. I'll see him in a few days, I need time to adjust after the assignment. My phone hasn't been reconnected yet, I haven't slept properly in over a month." They're poor excuses and sound hollow to both of them.

Casey settles back against the back rest with a thud and a scowl on her face. She crosses her arms over her chest and Olivia expects her to refuse out right but she relaxes a moment later and takes pity on her. "A few days?"

"A few days, I promise."

Casey gives her another appraising look. She clearly disapproves of Olivia's choice and reasoning, but she reluctantly nods, unwilling to be the go between for her and Elliot.

Days later, Olivia keeps her promise to Casey. She owes her that at least, Elliot hasn't come pounding on her door, demanding an explanation. She's managed to psych herself up on the words of the other woman, hopeful her return will be welcomed rather than be met with hostility. She wants to test the waters with Cragen, he was pissed at her for pursuing an uncooperative victim. She isn't worried about him holding a grudge, he won't. He's fair and she doesn't expect him to make any exceptions for her. Even if there isn't space for her now, she wants to have the opportunity if it arises in the future.

The scene that greets her is the opposite of what she expects. The squad is unusually quiet for this time of day. In fact, she didn't see anyone she recognised as she walked through reception and up to the bullpen. Maybe they all had calls. She cautiously pokes her head around the door, sweeps her eyes around the bullpen. Fin's, Munch's, and Elliot's desks are all empty. Only hers is occupied by another woman. She doesn't know why she's taken aback but a pang of possessiveness overcomes her as she looks at the desk, annoyed at the clutter which scattered her desk. Her old desk, she reminds herself.

Taking a deep breath, she interrupts the woman's paperwork and asks about Elliot. She boldly stakes her claim as his partner and Olivia steps back a fraction, any hope of reclaiming her place dashed. Self-preservation and shock stops her from introducing herself, suddenly she wants to be far away. Seconds later she retreats to the safety of the Captains' office, watching her replacement as she half listens to Cragen tell her he'll try to work something out in a few weeks. She tells him not to bother, makes some excuse about not being ready to come back. And she's not, not now. Not when Elliot leans over Dani comfortably and she isn't bothered by his hand on her shoulder. She recognises the familiarity, the signs.

In all the time she was in Oregon, she never expected this. He's held her at arm's length for more than a year and yet his new partner is able to cosy up to him in less than a month. All of the emotions are overwhelming and the small office is stifling. She needs to get out there. She mumbles a quick and strained farewell to Cragen. He stops her as she reaches the door and gestures to Elliot in the squad room. She repeats the request she made to Casey.

"Don't tell him I was here."