First off, I am so sorry for this. I don't know what came over me, I was scrolling through tumblr and this just...assaulted me and wouldn't go until I had it written down.
Title and summary taken from the song "So Cold" by Breaking Benjamin. I thought it rather fitting.
She was pale, lips tinged with blue, and though the night was warm her every breath was visible. Killian froze, flask slipping from his hand and clattering loudly on the wood of the docks.
"E-Emma?" His voice was barely above a hoarse whisper, blue eyes wide and disbelieving. She smiled, head tilting to the side, fall of pale blonde hair cascading over her shoulder. "But...how?"
Stepping forward Swan pressed a cold hand against his cheek and the pirate shivered, chilled to the bone at her touch. "Killian," she breathed, moving so close that, if he were to rock forward on his heels, their lips would be touching-and oh, how Hook longed for just that: to feel her mouth under his, hard and unyielding as they battled for dominance, pulling her body against his so that he could feel every inch of her, claiming and branding and simply giving in to what had always been between them.
But Emma had been dead for months, ever since Elsa had trapped them beneath the ice, and no matter how much Killian wanted, it simply wouldn't happen.
Resisting the urge to blink, fearful that she would disappear if he did, his eyes met her clouded green ones. "To what do I owe the pleasure, love? Come to torment me, a lovely, drunken vision of the one thing I long for but can never have, aye? Yes, that's what you are." His words were slightly slurred, and to any passers-by he knew that he must look mad, talking to himself and swaying drunkenly, but Hook didn't care. Anything to keep her near me, even for a few moments.
There was something almost tender in the way she looked at him, other hand moving up his chest to rest just above his heart. "I've missed you so much, Killian."
"And I you, lass, more than you could ever know." Tears burned behind his eyes at her sad smile, hand leaving his face to reach down and gently grab his hand; her skin was like ice, but he didn't care. It was still just as soft as he remembered, and Killian relished in the feeling of it.
Her next words caused his entire body to tense. "We could be together again, if you wanted." The fingers against his chest rubbed lightly, the chill seeping through his shirt and freezing the skin there. Killian was paralyzed, unable to look away from her terrible, beautiful face, the eyes that were once so bright and full of life now dull and staring.
"H-how, love? You're dead, there isn't a spell that can bring you back to me." Emma's answering grin was teasing, so horribly familiar a sharp ache in his chest had Hook struggling for breath. As the pain grew a bit of his drunken haze receded and the pirate looked down, gasping at the sight of her hand slowly sinking into his chest. "Emma?"
"Shhh." It probably should have frightened Hook, what he knew was happening, but even dead he trusted his Swan. The pressure grew until it was outright agony, Killian resisting the urge to double over screaming with the pain of it; that would certainly draw attention. Emma's icy hand closed around his heart and with a sharp tug she pulled it out of his chest, Hook staggering backwards and heaving a breath.
The beautiful ghost of his Swan held the dark, glowing heart carefully in her two hands, cradling it against her chest as though it were something precious; for all he knew, even dead, it was. Raising her hands up so that she was holding the heart out slightly, level with her shoulders, their eyes locked as she pressed them together, his heart caught between them, and Killian couldn't help the scream that escaped him as she crushed the beating organ between her icy palms.
Lights flickered on in the distance, his cries waking more than half of the town, but the captain was too far gone to notice; his entire being fought against the pain, the sheer unreality of the situation, as he dropped to his knees. The edges of his vision were slowly going dark, the grey fog threatening to consume him; eyes never leaving Emma's face, he smiled brilliantly as the heart began to crack, flecks of dust beginning to fall from her hands.
"Love," he whispered, falling forward and resting his weight on his hands, "Emma..."
"Killian," she said again, voice an ethereal echo in the encroaching darkness. It was a struggle not to collapse, every breath, blink, fucking thought labourious. Footsteps could be heard faintly in the distance and Emma broke eye contact, pure agony crossing her lovely features as David's voice rang out, echoing off buildings. Killian watched as she hesitated, the heart so close to shattering in her hands; the sudden thought filled his mind, that she wouldn't go through with it, that she would be stopped-he would be left alone, to live a half-life, damaged heart thrust back into his chest.
"No!" With a last burst of energy Killian surged to his feet, staggering towards his frozen love, hands closing around hers and pressing, squeezing, crushing his heart between their hands. Their eyes met one last time as he fell, mind blissfully empty of every thought save her, the pain fading and leaving nothing but a glorious emptiness behind. As his body hit the docks, the last thing he saw was Emma's gorgeous smile.
I'm coming for you, my love.
Wait for me.