CHAPTER TWENTY FIVE: IT'S OVER

It all happened so fast.

One moment, Luca's case files were gathering dust in their desk drawers and the murder board was almost ready to be dismantled, and the next they had a thumb drive with both Luca's and Jason's prints all over it.

And everything they needed to close their investigation.

It was a blur.

Flashing lights, blue sirens that shone from the back of their black GMC Sierra as the brakes screeched on tarmac and rolled up outside of Mateo Herrera's motel room; Erin barely had time to register Jay's firm hand settling her stomach as he placed it just gently in the small of her back before they grabbed their service weapons from their pockets, cocking the guns and sprinting stealthily to room 384 and smashing the door down.

CHICAGO PD!

Torch beams searched where their eyes couldn't, and they found their target.

Metal handcuffs.

Miranda rights.

More sirens.

Hearts pounding in chests from anticipation and exertion.

And fear.

Erin sat in the boot of the Sierra, her legs dangling as she watched him being led into the back of the police car; Jay noticed her white knuckles and her fingers balled into fists and he tried to place a hand over hers in comfort but she shook him off and clenched her jaw, her eyes set on the man in front of her, and before he could even think about doing something, Erin was on her feet and running towards him.

"Hey!" she yelled, so loud her already husky voice sounded like a roar.

The uniformed officers turned around, Herrera in between them turning to face her.

Erin got right up close to him, so close that she could feel his disgusting breath on her face. "Do you have any idea what you've done? Luca Sanchez was seventeen!"

Herrera just smirked, and the fury welled in Erin's chest until her fist acted of its own accord and before she knew it, her knuckles had collided with his jaw and he stumbled back, spitting onto the floor.

"Seventeen!" Erin roared at him again and she felt the strong hands of Jay, Atwater and Kim restraining them. She struggled against their arms but they held on.

"Erin," Jay murmured into her hair, and she relaxed slightly, the sound of his voice finally dragging her back to reality. "Erin…"

They let go once Herrera had been loaded into the back of the police car, and Jay stared at her.

"What happened? Erin?"

She looked up at him, trying to will herself not to burst into tears in front of everyone, but…

But she couldn't. Damn it. All she needed was to look at Jay and she didn't care about what anyone else in the world thought of her.

Her face crumpled, and her hands jumped to her face, covering her mouth to stifle a sob.

Atwater turned away, abruptly and Erin couldn't be more thankful for his small gift of privacy, dragging Kim, who wanted to see that her friend was okay, away from the two partners.

Jay did a quick look over his shoulders to check for Voight, but decided he didn't care and pulled Erin to his chest anyway. When Voight did turn around and see them, he was ready to march over there and give them a piece of his mind about showing their relationship in public – while on a call, no less – before he noticed that Erin's shoulders were shaking and Jay was doing his best not to burst into tears too.

Voight met Jay's eyes over Erin's head, and he gave him a small nod.

Take her home, Voight mouthed, and Jay nodded back.

"Come on," he whispered, and they got back into the car. Erin hiccoughed slightly, and Jay took her hand in his and didn't let go the whole time they were driving.

"Avery, honey, can we talk to you?" Erin knocked on Avery's bedroom door gingerly, Jay hovering behind her.

Avery nodded and pulled out her earphones, tossing her homework aside and shuffling over on the bed to make space for the two adults.

"Sure, what's up?" she said.

"We, uh…" Erin took a deep breath. "We caught a break in Luca's case," she said slowly.

There was a long silence, that stretched between them like oceans.

"We got him," Jay whispered, laying a hand on Avery's shoulder. "Where he's going, he's never going to hurt anyone ever again."

Avery nodded. Her eyes filled with tears and she bit her lip.

"You really got him?"

Her chin was wobbling.

"Yes, baby, we got him," Erin said in a rush and pulled Avery in for a hug. "It's over."

Avery didn't respond to that and instead she held onto Erin's shoulders. Jay put his arms around the two of them and together they sat on the bed, holding Avery as she sobbed into Erin's shoulders.

"It's over," Erin repeated, and then she met Jay's eyes over the top of Avery's head.

It's over. They both knew she wasn't just talking about the case.

The hallways of the twenty first district had never felt as long and as cold and as unwelcoming as they did the day Avery Murray was called in to identify the man who murdered her best friend Luca Sanchez. Although the evidence had stacked up against the guy – forensic as well as their standard motive, means, and opportunity – Voight wanted to make sure there was no doubt about it. No loose ends that could swing a jury or prevent this monster from spending the rest of his days behind bars.

And one thing that usually stood up in court, provided they could be proven to be reliable and credible sources, of course, were witness statements and positive identifications from people who were actually there at the scene of the crime.

And although Erin and Jay both knew that Avery's witness statement could, and would, only serve to strengthen the mountain of evidence they already had against Herrera, rather than make or break the case, the memory of Nadia's trial and Erin being put on the stand and forced to discredit her murdered best friend was enough to make the both of them reluctant to put Avery through a trial.

But they'd spoken to her about it, and as Erin had suspected, she wanted to testify. She positively identified Herrera out of a lineup with absolutely no difficulty whatsoever, and demanded that Erin allow for her to be put on the stand.

Erin wasn't so sure; the doubt had sown its seed in her belly and just wouldn't go away. Later that night when they'd got back to the apartment, Erin knocked gently on Avery's bedroom door and nudged it open with her toe.

"Listen, Avery, I want to talk to you about the trial - about you testifying against Herrera. I just...don't know if that's a good idea," Erin protested. "A trial's gonna be very difficult – they're gonna want to dig up everything they can to discredit you, and pick you apart on the stand, and…"

"Don't you think I'm ready? I can handle it," Avery shot back. Jay, who was in the room next door while all this was taking place, wanting to give them the space they needed to get this conversation done with, smirked slightly at how much Avery sounded like Erin already.

"That's not it," Erin shook her head.

"Erin, he was my best friend!" she pleaded. "Besides, you owe me at least this."

Erin raised an eyebrow. "I owe you for what, exactly, young lady?"

Avery sighed. "I wasn't gonna bring this up, but I expected that you would, and you haven't, and it's been four days already since you caught him, and I really think we should talk, or at least acknowledge, or something, and…" she rambled. Erin frowned, concerned.

"What, Avery?"

"You've caught Luca's killer. I don't need to be in protective custody – or whatever the hell this even was – anymore. So we're back to square one. If you're just going to boot me out as soon as you can, you can at least let me help put my best friend's murderer behind bars!"

Erin was speechless. She'd had no idea that Avery was so bitter about this whole thing.

"Avery, love, you've known all along that this was only a temporary placement."

Avery's face fell. Whatever she'd wanted Erin to say, it wasn't this.

"So that's it?" her voice was weak and dangerously close to cracking. "After everything? You're not even gonna fight for it? For me?"

"Avery, that wasn't what…" Erin trailed off.

"Save it," Avery spat back at her, and stormed out of the room, grabbing her keys and coat, and stomping right past where Jay was preparing food in the kitchen and out the front door, slamming it behind her. The slam ricocheted through the apartment walls and made the decorations on the Christmas tree tinkle.

"Avery!" Jay tried to call. He stopped what he was doing as Erin came to join him. "What happened?" he asked softly. He knew already, of course, he heard most of it, but that wasn't really what he was asking, and they both knew it.

"I don't know," Erin whispered.

Jay quickly brushed his hands down on his jeans, and walked over to where she had sat down at the breakfast bar. "Hey, it's okay. She'll be okay. She's just shocked and emotional because of Luca, and the case, and she's taking it out on you. She knew this was temporary. You shouldn't have to feel pressured into anything you don't want to do."

He put his arms around her and she leaned her head into his torso, stroking his arm. Her eyes drifted shut.

She couldn't help but question how her boyfriend could know her so well – her little habits and tiny insecurities and the way she sleeps and the depth of her breathing and the way he could notice even the smallest change in her mood as if he were a puppy who could smell her fear – and yet he was so completely oblivious to how she was feeling right now.

"When I first offered Avery to come and stay here," she said so quietly it sounded like a tiny, rattling breath, and Jay almost didn't hear, "she asked me why. She said, 'Why should I believe anything that comes out of your mouth when I know you're just gonna chuck me back into the system again the second I've helped you with your case?' and I told her, 'because I am the only person right now who is fighting for you.'"

Jay smiled against the top of her head, where he had rested his chin. "You were right. You were the only chance she had at getting through Luca's death, of getting clean…Erin, you have literally saved that girl's life."

Erin shook her head. She pulled back from Jay and looked up at him, her eyes terrified. "Did I… Jay, did I lie to her? Am I giving up on her now?"

"Shh," Jay said. "Of course not. This was always the plan."

He crouched down slightly so that he was properly at her height, and he wrapped his arms around her. She reached up, and rested her head into his neck, opening her eyes slightly to see the door to their apartment completely shut, where Avery had stormed out a few minutes ago.

The sound of the slam, shattering the silence, still sounded in her ears.

She frowned.

She pulled back from the hug.

"Oh my God," she whispered.

"Erin?" Jay stuttered, worry seeping into his words. "Is everything okay?"

She pushed him back. "No. I need to go. I need to go after her."

And she, like Avery, grabbed her parka off the railing in the hallway, shoving her bare feet into her combat boots without even bothering to tie her laces, grabbing her keys off the mantelpiece and running out into the snow that was lashing down onto the streets of Chicago.

"Erin?!" Jay yelled after her, but she left him standing in the doorway of their apartment as she dashed out into the night.

Oh, she was an idiot.

She wasn't upset because she'd lied to Avery; she wasn't upset because Avery was upset.

She was upset for the exact same reason Avery was.

Erin didn't want her to leave either.

She just hoped it wasn't too late.