She stares over at the Chicago skyline, his words repeating over and over in her head. "Don't look back." The FBI was a big deal, much bigger than Intelligence. It was all happening so fast. She turns the dog tag from Hank over in her hands, her thumb tracing the spot where his was imprinted.

Her ringing phone pulled her from her thoughts. Jay Halstead. The name lingers on the screen before she turns it off. It didn't have to be harder than it already was. She takes one last look at the city she'd protected with her life. There was no turning back now.

She can't look out of the plane window. She wants to, she doesn't want to. The entire two hours, she keeps her head down and reads through her case files.

Jennifer Spencer was waiting for her at the airport. She greets Erin cheerfully, and quickly leads her away from the bustling crowds.

New York. It's so different from Chicago. She's been here before, only this time she wouldn't be going home. They stop at her new apartment first. It's furnished with comfortable, modern furniture, one of the luxuries of working for the FBI. It was obviously supposed to feel homely, but she knows already, it would never feel like home.

She's introduced to a few other agents at headquarters. There are so many, she can't remember them all. She gets straight to work, trying to distance herself from the growing guilt in the pit of her stomach. Her fingers find their way back to the dog tag in her pocket. She misses Hank, she misses Jay, she misses everything she'd left behind.

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"She'll be here," Will had told him. He calls her, but she doesn't pick up. He leaves, the small red box heavy in his pocket. Molly's wasn't the same without her.

She doesn't show up to work. Voight says she was in New York, but that didn't make sense. Why would she just leave all of a sudden? She didn't even say goodbye.

He knows she was going through a lot. With the board, her mom. But he needs closure, he doesn't want to end it like this.

He goes to her apartment after shift ends. The furniture is still there, but her things are gone. The pictures that once decorated the shelves and walls, the posters, all gone, nothing left to indicate that Erin Lindsay once lived here. Until he finds the boxes in the closet. Underneath one, there's a photo. He remembers that day well.

He looks at it for a long time. He folds it in half, then in half again, and goes to put it in his pocket. His hand hits something hard. His heart sinks.

He pulls the red box out, turning it over in his hands. Would she have said yes?

He stuffs it back in his pocket with the photo and leaves the apartment. She was gone, she wasn't coming back.

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Her first day went as smoothly as she could expect it to be. She checks her phone, expecting missed calls. Nothing. Was he angry? Probably. She feels the familiar ache in her chest, but she ignores it. She hates that she has to keep reminding herself to move on.

The FBI isn't like anything she's used to. It's so much more official. Her new partner, Jefferson, was good, but he's not Jay. He was too uptight, serious. They just didn't get along the same.

Their stiff and uncomfortable silences were nothing like the playful, casual conversations with Jay. After she was done for the day, she lets herself have one good cry.

She pulls herself together, and dials Hank. He answers immediately. He asks how New York is, she tells him everything but the truth. She doesn't want to disappoint him, not now.

It's good hearing a familiar voice, and she feels better. At least, that's what she tells herself.

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He goes to Molly's after leaving her apartment. At least he wouldn't be alone there. He keeps the drinks coming, pushing the consequences to the back of his mind. He doesn't want to go back to an apartment that's too quiet, back to a bed that's too empty. He stays until the bar closes, long after everyone had already left. Will has to come pick him up. It's almost four in the morning when they arrive at his apartment. By then, he's completely gone.

Will stays with him all night. He can't leave his brother by himself, not when he's like this.

The alcohol had numbed him, but then he couldn't control himself. The words kept pouring out. He lets all his misery, his longing, his desperation out into the open. He passes out soon after, eyes wet with tears he'd tried to suppress.

The pounding in his head is so much worse when his alarm goes off. He's a mess. His reflection glares back at him as he stands in front of the mirror. He hasn't seen this version of Jay Halstead in a long time.

He cleans himself up as fast as he can. He could distract himself at work. Or that's what he hoped. Every time he tries to focus, his eyes keep wandering back to the desk across the room, empty.

Hailey Upton was his new assigned partner. She's good police, he knew that from the start, but she just wasn't Erin. That was the thing about Erin Lindsay, she was one of a kind, irreplaceable.

He calls her again, and this time she picks up. Their conversation doesn't last long. She doesn't tell him much; neither does he.

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He hates the mornings, when he'd wake up and subconsciously reach an arm out, expecting to feel her there. He hates that his hand brushes over cold sheets, filling him with the sinking disappointment he can't seem to shake away. He hates that Will stands in the kitchen, instead of her holding a steaming mug of coffee when he walks in. He brushes off his brother's concern and heads straight to work. He's the first one in, and the last one to go. Everywhere he looks, he's reminded of her.

The memories they'd shared in the bullpen, the locker room, the breakroom. That trademark Erin Lindsay smile he loved and missed.

He barely spent any of his time home anymore. Home. That word stuck in his mind. The last time he'd called a place home was when he'd lived with her. He couldn't help thinking, maybe if he didn't move out, this wouldn't have happened. If he didn't walk out that door, if he'd stayed, maybe instead of sitting by himself on a cold barstool, they'd be having one of their conversations in the car or sipping coffee in the breakroom together.

He brings the bottle to his lips again, but only a single drop comes out. He sets it down and orders another.

He was surprised to see her name flash across his screen. It's unexpected, but he's happy she called. They make small talk, ask questions about each other's lives. A few attempts at jokes are thrown in here and there to try and lighten the mood.

"I miss you," she says. He doesn't know what to say back. But after the long days he's had, those three words mean everything. He wants to tell her he misses her too, that he wishes she'd come back more than anything in the world. Except he doesn't and keeps it to a simple goodnight. Some things are better left unsaid, he decides.

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She can hear the exhaustion in his voice when he picks up. He insists he's fine, but she notices his tone change as he says the words. His voice is weighed down by the tiredness he's trying so hard to hide, and she knows. He knows she knows. But neither of them say anything.

She tells him she misses him. It's the truth, probably the only one she's told so far today. She hears his breath grow unsteady and it's silent for a moment, then she hears his goodnight. It's softer than before, his voice barely above a whisper. She's disappointed he didn't say it back, but she pushes the feeling away after hanging up. She was the one who left, she doesn't even have the right to be disappointed.

Her phone is thrown carelessly onto the bed, and she rolls over to face the window. She watches the cars below come and go. The lights eventually pull her into an uneasy sleep.

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The time between each phone call grows longer and the number of missed calls on her phone drops to zero. She tells herself it's for the best, but she really wishes it didn't have to be. She stops checking her phone as much, she puts her head down and works harder.

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He calls her less and less, and the times she actually picks up, she always sounds distanced, distracted. Their conversations are short and neither of them have much to say. He stops calling altogether, telling himself it's better that way, to just let her go.

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It's almost been a year. She's moving up in her unit, a few promotions away from leading her own small task force. She's made a few good friends and settled in better. Hank still calls regularly, and she's grateful for it.

She's getting ready to go to sleep at a normal hour for once when her phone buzzes and Hank's name flashes across the screen. She's tempted to let it go to voicemail, because honestly, she's exhausted, and every part of her wants nothing more than to just collapse onto the bed. But when he calls a second time, then a third, she gives in, and accepts the call.

She notices the urgency, the desperation in his voice when he speaks. His voice breaks, and she has trouble understanding what he's saying. She can swear her heart stopped when she's finally able to comprehend his stuttering. She's stuffing clothes into a small suitcase, holding her phone between her ear and shoulder, promising that she'll be on the next flight out. Al's in the hospital.

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She stands at the back, not too far, but far enough so that she won't be noticed. She owes it to Olinsky to be here at the very least. She can't stop the tears from escaping. He was a friend, a father, and damn good police. It's all her fault he's gone. She shouldn't have asked him to help move the body. She shouldn't have been so careless. It should've been her in the prison cell, in the coffin.

She watches his coffin being slid into the back of the car. She can see the unit, with hard faces and each with a hand raised to their foreheads. She stays until everyone leaves, figuring it's better not to risk being seen. She's walking to her taxi when a familiar voice calls her name. She doesn't have to turn around to know who it is. She'd recognize that voice anywhere.

She sighs and turns to face the one person she wanted to avoid. And of course, he looks better than ever, in his uniform and blue eyes fixated on her.

"Hey, Jay."

"What are you doing here?" He doesn't sound angry, so she figures that's a good sign.

She shrugs, "I wouldn't miss Al's funeral."

He nods slowly, unsure of how to continue. "How have you been?"

"Fine." It's a classic one-word response she uses when she's everything but. He knows that. He offers her a small smile, but it doesn't reach his eyes.

"I can't believe he's really gone," she sighs, the exhaustion from the last few days finally making its way into her voice.

"How long are you staying?"

"A few days. I fly back on Saturday." Her hand moves to play with the zipper on her jacket. His heart sinks, but he never expected her to just come back for good. A few moments of silence pass before he talks again.

"Can I buy you a coffee?" he asks. "You know, for old times sake." The corners of his mouth tilt upward into a hopeful grin.

She hesitates, and for a second, he thinks she's going to say no.

"I'd like that," she finally says. It's only three words, but it's enough to make his whole day. Quite possibly his whole week. Then that trademark Erin Lindsay smile is on her face, dimples and all and he can't stop grinning either.