This is a one-shot born from a Swan Queen kiss manip I made for tumblr, and had to write a story behind it. This is after the final scene in season 4, when Emma sacrifices for Regina's happiness.
The night is Dark but Light will find its way back.
Regina's hands were shaking as she held the dagger in them. They've tried summoning the Dark Savior right after the dagger hit the ground, but Emma didn't answer to their call.
Absorbing all that darkness had left Emma in a haze, weakened, and in some place she couldn't quite recognize. Blurry images flooded her mind; her family, her life before Storybrooke, her experience in the Enchanted Forest — everything was spinning and she couldn't tell one from another.
She'd heard the call in between her nightmares but she was unable to respond. Everything turned black; she lost conscience, and fell to the cool ground.
When the light of sunrise filtered through the cracks in the cave she'd spent the night, Emma started to wake up from her slumber, and then heard someone call her once more. She felt something tug inside her stomach and drag her to the presence of whoever was the owner of that voice making her every fiber vibrate with an indecipherable feeling.
"Dark One, I summon thee."
When Emma finally appeared Regina felt relieved, but the blonde wasn't welcoming having an audience surround her. All the faces were strange — or not. She couldn't decide. They felt familiar but at the same time she couldn't recognize them, and it made her anxious and before Regina could make an order, the new Dark One waved her hands and made everyone but the one holding the dagger, and the boy that was beside her, vanish to outside the building.
"Emma… How do you feel?" The brunette asked worriedly but she was the one trembling.
"Emma? That's… my name… Yes. I am fine. How may I serve you, Ma'am?"
Emma asked the other woman as she took a step closer to study her features, trying to recognize her. She was sure she'd heard her voice before, and it made her feel odd — like the darkness faded away when the other woman spoke to her. It was somehow soothing to her ache.
"You don't know who we are?" Regina became more worried.
Emma wielded too much power — dark magic — and didn't remember her family, or anyone apparently, and that made her even more dangerous. How would they make it work if she didn't even remember them?
"I'm Regina, Emma. Please try to remember."
"Regina…" The name somehow felt natural in her lips as she repeated it, and images of coming to Storybrooke and meeting the mayor, flooded Emma's vision.
"And I'm your son," Henry said after.
"Henry?" Emma recalled the name from the memory of that day he showed up at her door.
"Yes!"
Henry ran to Emma's side to embrace her, but she felt startled and a blast of magic from her body pushed him away, making him fall and lose conscience. And then her magic started making her hands glow with fire, ready to hurt her own son, as her eyes flickered pitch black.
"No! I command you not to hurt our son," Regina quickly ordered, and the fireballs in Emma's hands turned to smoke.
Regina ran to his side and stepped in front of Henry to protect him from his other mother.
"Our son…" The words echoed in Emma's head, and her eyes turned back to normal. "I… I think remember now," she walked up to Regina, who took a step back in fear.
"Don't hurt us, or anyone else," Regina commanded as she wielded the dagger.
"I'm sorry. I would never purposely hurt you," Emma's stare turned into a soft gaze. "You're the only sparks of light that are left in my darkened heart," the Savior told them.
"I made you a pro—" Emma suddenly fell on her knees.
The darkness started coming out of Emma's pores to wrap around her like a snake, and Emma's eyes began turning completely black as the darkness possessed her again.
"No! Emma!" Regina ran to her side, "Please don't give in to darkness, you can defeat it," she cried out.
"Regi—na," Emma was chocking, and her eyes kept going black and getting back to green in her struggle to defeat it.
"Please don't leave us," Regina held her in her arms as she saw the light leave her eyes. "Come back to me."
No one could break through the magical barrier that Emma had cast when she sent them away, and Regina's only hope now had been Henry, but he lie unconscious and she couldn't do anything to stop Emma's heart from losing all its light.
Not unless she… No. It wouldn't work, but it was her only chance.
"It was always you… How couldn't I see it?" Regina's tears fell. "I know I'm not your happy ending, but if our True Love for Henry can make this work, I promise I will help you get yours."
Regina stilled Emma's face in her hands and got closer. "I love you, Emma," she said before kissing her cheek, and tears continued trickling down her face.
An explosion of light burst from Emma's body, and the darkness vanished to disappear into thin air forever, together with the dagger.
"That was true love's kiss," Henry said as he slowly got on his feet.
Regina was very surprised, even more than her son, and kept looking at Henry with disbelief.
"Regina?" Emma's hand went to Regina's cheek, and jade eyes gazed into brown.
"You're wrong," Emma said to her.
"Excuse me?" Regina shook her head in confusion.
"About my happy ending," Emma tried to stand up but was still weak, and Regina held her as both remained knelt facing each other.
"How so?" Regina blinked her eyes and looked hopeful.
"My happy ending is you, and Henry," Emma told her as she cupped her face in her hands gently. "My family," she paused to take a deep breath. "My true loves."
Emma slowly began leaning, closing the distance between them, and as she did, the world seemed to have stopped for the both of them, and they didn't care for what was happening around them. Mary Margaret, David, Hook, and Hood had finally broken through the weakening magical barrier, and were watching with disbelief what was happening before them.
They'd thought Henry had given Emma True Love's kiss, but now it seemed not.
Their lips met in a shy, soft first kiss that was filled with light and the promise of a happy ending, and Emma and Regina felt finally complete. The last piece of the puzzle to their happiness had been right in front of them all this long, but they hadn't taken it because they both thought their love was unrequited. Well, not anymore.