A/N: Inspired by this prompt from the castlefanficprompts page on tumblr:
Knockout AU: Montgomery gives Beckett to Lockwood in order to protect his family.
The message of warning from the boys had come too late. Face to face with Montgomery, the third cop with a gun in his hand, she knows it's too late.
"Put the gun away, Roy," she commands, voice even but her hands tremble, fingers skirting her side, hovering above her own service piece.
"Kate, I'm not going to jail for this, I can't put my family through that."
So many questions fight for attention amidst the whirlwind of her mind, but only one word is able to leave her lips.
And she almost wishes she hadn't asked. Almost.
Roy Montgomery spills his sins to her, lays them out on the floor of the airport hangar, and for one horrible second she's convinced that this man, this man who has become something akin to a second father after all these years, was the one to murder her mother. His answer of denial brings her momentary relief that is quickly outweighed by the betrayal he has bestowed upon her.
"Give me a name. You owe me that, Roy."
"I give you a name, I know you, you'll run straight at it. I might as well shoot you where you stand."
"That's why you brought me here, isn't it? To kill me?" Her heart cracks with the question, years of trust and friendship shattering to pieces within her chest as she watches her captain divert his gaze to the dirty hangar floor.
"No, I brought you here for them." Beckett follows the trail of his eyes to the flicker of headlights in the distance. "If you would have just stopped, if you would have just let it go…" Roy shakes his head, lips pursing with shame or disappointment, perhaps both. "We wouldn't be here if you would have just stood down."
"You said - you were supposed to stand with me." Her throat is dry, panic swarming in her chest as the glow of headlights steadily grows brighter.
"They made me choose, you made me choose," he rasps, backing away from her, back into the shadows. "And I have to keep my family safe."
She had once thought that family was more than blood.
"I'm sorry, Kate," Montgomery chokes out. "I'm so sorry."
The headlights cut off, going dark, the car speeding up, and Montgomery has disappeared. Abandoned her.
Kate withdraws her gun, clutching it between both hands as she surveys the airport hangar for some sort of cover. She'll take them on, all of them, and she'll damn well fight them to the death.
Beckett startles so harshly she nearly drops her gun. Spinning on her heel, she sees Castle racing through the back entrance, running towards her with Ryan and Esposito in tow.
"Castle?" she breathes, but there's no time to ask how they found her. The SUV is roaring towards them, coming to a screeching halt to reveal Lockwood and four other armed men exiting with weapons trained on them.
"Well, look at this. Going to be a four for one kind of night?" Lockwood muses, that wicked smirk she's grown to recognize unfurling on his lips, but no life in the ice blue of his eyes. "You know, we could all save ourselves some trouble if you just handed over the one we came for."
Castle's chest brushes her back, his shoulder coming into contact with hers as he positions his gun, the backup piece from her desk, in unison with Ryan and Esposito. Her ribcage shudders with dread, three men she cares deeply for all ready to sacrifice with her, for her.
Kate lifts her gun.
Lockwood releases an exaggerated sigh. "Don't be stupid, you're all going to-"
She isn't sure who fires the first shot, but the second a bullet pierces the air, the chaos begins. Lockwood's men go down quick, Esposito's sniper training combined with Ryan's quick trigger finger eliminating the henchmen like paper targets, but Lockwood is faster, better, and evades the gunfire, dodging and weaving, using the darkness to his advantage.
Beckett's team forms a square, Ryan and Esposito back to back while Castle covers hers, weapons aimed and ready, but the moments of unsettling stillness tick by and Beckett signals they split up, the boys taking the left side of the hangar while she and Castle investigate the right.
"Stay close to me," Kate instructs under her breath, feeling the warmth of her partner at her side and a strange sense of peace settle over her racing heart for that split second.
"Always," he mumbles, his voice gruff, his eyes piercing and deadly when she spares a glance towards him.
They drift towards the parked helicopter together, footsteps silent but in sync, and scan the inside of the aircraft. There are only so many places to hide in this place, even with the shield of darkness aiding. Lockwood has to be-
The ripple of movement reflected in the gleaming surface of the helicopter catches her eye a second too late, but not for Castle.
She jerks around, braces for the impact of a bullet, but receives the slam of her shoulder into the floor beneath instead, the weight of Castle on top of her, gun raised and firing multiple rounds into a man already struck and staggering to his knees.
"Castle! Cease fire!" Esposito shouts, running past the two of them with Ryan on his heels, and Kate shifts to her elbows, swallows past the lump of panicked adrenaline in her throat and reaches for Castle's wrist, for the gun still poised and prepared to fire another round in his hand.
"Rick," she chokes, drawing his arm down until the gun rests on the floor beside her hip.
Castle tears his gaze away from the dead man a mere ten feet away, focuses his eyes on her instead and parts his lips to speak, but before words can form, he's hissing sharply, hovering his palm over his shoulder.
"Kate, I think - I think I was shot."
Her heart plummets in horror and Beckett scrambles to her knees, following his line of sight to the edge of his right shoulder. She gingerly places her hand to the spot, winces at the hot spill of blood, the gasp of pain that escapes him as they shift to prop him against the side of the helicopter and he tries so very hard not to collapse into her.
"I'm sorry," she gets out, leaning over him, applying pressure to the wound, but that isn't what she's apologizing for and he knows it, sees it when he lifts his agony clouded eyes to her. "I'm so sorry. I'm sorry-"
Castle wraps his good arm around her, cradling her trembling frame to his chest even as the pain must wrack his body, burying his face in her neck. It's an awkward position, kneeling above him with one of her hands sealed to what feels - thankfully - like the graze of a bullet rather than an entry wound, but she strokes her unoccupied hand at his jaw, soothes both him and herself with the caress of her fingers at his skin.
"We're not over," she whispers, the sob building in her chest. Their fight, Montgomery's betrayal, the man she… the man she thinks she may love shot and bleeding - it's all too much. "We're not-"
"No," he agrees into the skin beneath her jaw, fisting the hand at her back in the fabric of her turtleneck. "Not over. Never over."
"Yo Beckett, we got an ambulance on the way," Esposito informs her while Ryan trots over, holding out his jacket to apply substitute for her hand on Castle's wound. "Did you see where Montgomery went?"
Castle holds her tighter when her breath shakes its way past her lips.
"No," she calls over her shoulder. "But I assume he's going to take his family, make a run for it, try to disappear."
"I - I think I hate him," Castle gets out beneath her, drawing her attention back to his paling skin, his fluttering lashes and waning consciousness. "For what - what he's done to you."
Kate sinks a little further into his embrace, desperate to keep him awake, to make him stay with her until the ambulance arrives.
"I don't think I can hate him," she whispers back, still stroking along the line of his jaw, abrading her fingertips on stubble. "He made a choice. Chose his family."
"That doesn't make it okay," Castle argues, quiet but firm, weak but furious beneath the pain, and Kate dips her forehead to rest against his, breathing past the stench of blood and engine fuel, inhaling the scent of his aftershave and coffee that lies within his skin. "How could anyone ever give you up?"
"Bus is here, Beckett," Ryan calls, standing at her side, ready to help if need be, but they wait for the paramedics to rush in first.
Kate shifts to move out of the way, untangling from their painful embrace, but Castle catches her hand, begs her with the fading blue of his eyes to stay.
She twines their fingers and sits on her knees by his side as the EMTs assess the graze that ripped through the outer edge of his shoulder. He'll have to be transported to the hospital for the wound to be cleansed and stitched up, but he doesn't have to ask her to join him.
Kate remains at his side, assisting the medical team in transferring him into the back of the van, climbing in to take a seat by Castle's head, combing her fingers through his hair after they've strapped him in and started the engine. His eyes fight to remain on her, trained steadily on her face, but the rise and fall of his lashes slows with each passing second, awareness fading.
"Don't disappear," he slurs, managing to hook his fingers in the back of her knee, clinging to the denim of her jeans.
"I won't," she murmurs the promise, skimming her thumb along the path of his eyebrow and bowing over him to press her lips to his ear when she's certain he's gone. "I love you. I'm not going anywhere."