In the horrified silence that follows the Dark One's vanishing act, a vow echoes painfully in Killian Jones' head, like a heated bullet glancing off jagged rocks.

This is not how their story ends.

Not like this.

Since the very first moment they met, she has caused him both immeasurable joy and inconceivable grief. Until this moment, he has regretted little more than a few moments of their addictive thrust and parry.

Tonight wasn't the first time he'd heard himself ask of Emma Swan that question in an anguished voice.

"Why are you doing this?"

She'd betrayed and chained him, left him to perish in a giant's lair, and perhaps he could be forgiven for being confused, given their alliance to that point.

(She'd left him to die without avenging the death of his love, and in that moment, he thought he knew despair. Clearly, he'd no clue of the despair that was to come.)

In the giant's lair, despite her betrayal, she'd looked at him with soft eyes, her face brimming with guilt and conflict, and he'd seen the glimpse of something else, something more behind her frightened retreat.

"I can't take the chance that I'm wrong about you."

Now, his blood is chilled as never before, the scent of something like brimstone lashing his senses as he stares at her, his voice choking in a tight throat.

"Emma, why are you doing this?"

She looks at him, her eyes harder than flint, betrayal and anger etching harsh lines onto her pale face. She is terrifyingly beautiful, her bones sharp, her hair ashen, and his gut curls up at the edges, his blood seeming to run even colder. She whispers the answer through hard, red lips, lips that have branded his more times than he can remember, and something inside him withers and dies.

"Because I'm the Dark One."

She watches him with an air of bleak satisfaction, waiting like a bird of prey, as if wanting to see him flinch at her words, then she's gone, leaving a eddy of blackened smoke in her place.

Killian Jones thought he'd known despair. He knows now that he had known nothing of the sort, not until this moment, because Emma Swan isgone. Once again the Dark One has stolen his love, leaving him crippled with loss and grief, his heart rent asunder.

But this is not how the story ends.

Not this time.