A/N: Big thanks to Starblaze Knight for today's prompt. I've had it outlined since June and I was SO excited to finally write it.

The poll has been updated.

Thanks for all your continual encouragement!

Happy New Year!

Prompt: An AU where instead of Leslie, it's Alex who is saved from a helicopter (DEO mission) by Supergirl and gains electrical powers. Kara helps Alex with her new abilities and together they save National City from an Alien attack, with sister bonding afterwards of course.

i.

"You stay safe, okay?" Kara said, lingering in the hall as Alex climbed the stairs to the rooftop, making her way toward the helipad.

"Of course." Alex pushed the door open and the wind caught her hair, thunder humming low in the sky as dark clouds rolled in.

"I'll see you out there," Kara said, blasting off the roof with her cape billowing behind her as Alex climbed into the helicopter. It wasn't supposed to be too bad, the mission was quick and simple: apprehend the alien before civilian lives were put in danger.

In and out before a raindrop even hit the ground and the storm began.

However, after five minutes in the air the wind began howling against the propeller and whipping between skyscrapers.

J'onn held the second team of helicopters back.

At ten minutes, a crack of thunder pierced the night and lighting split the sky.

J'onn called all units back to base.

"Wait," Alex said, turning to the pilot as the helicopter jerked and rain poured through the sides. "I see it, right there," she pointed toward a shadowing figure. "We can't leave. I'm calling the ground units in."

"With all due respect Agent Danvers, we need to get ou—" Another gust of wind sent the helicopter spiraling, the pilot was sucked out, sent tumbling to the ground.

Supergirl was passing the newly unconscious alien to a group of agents when she heard the man's screams. She shot into the air. All helicopters were supposed to be back, Alex was supposed to be safe, but Kara knew Alex's helicopter, had seen her sister climb in at the DEO as she'd taken off and she saw the same frame peeking through the clouds, thrown around by wind a few hundred feet in the air.

Kara caught the pilot just meters from a collision with the ground and deposited him to a medical unit before hurtling back through the clouds toward Alex. Her heart was pounding, a lump in her throat. The roar of thunder was magnified in her ears, her heightened senses buzzing as she was engulfed by storm, streamlining toward the center of the chaos with only one thing on her mind.

"Alex!"

Supergirl caught sight of her sister again, sped toward the plunging helicopter. "Alex," she screamed again, voice nearly drowned in swirling winds and sparks of lighting and crashes of thunder. "Grab my hand."

Kara's hand bumped Alex's, she curled their fingers together and Kara could hear Alex's heart beating just as fast as her own when a bolt of lightning struck the red of her cape, radiated through her body and was transferred to her sister, jolted in the night.

ii.

Kara wouldn't let go of her sister's hand. Not when Alex lost consciousness and they fell from the sky, not when medics surrounded them and lifted Alex onto a stretcher, rolling her into an ambulance. Nope. She kept their fingers entwined as they pulled into the DEO and she tried. She tried so hard to keep them together when the doctors rushed Alex away for tests and treatment. She fought. She fought every single lab coat clad individual until J'onn was called in to pry Kara's fingers from Alex's hand, only relenting when a tighter grip would have threatened to snap her sister's metacarpal bones.

So she sat.

She sat in silence as Alex was wheeled in and out, room to room, and until she was finally left where Kara was sitting. Alex was in a coma, they'd said, but she just might be able to hear Kara.

So she talked.

For hours she whispered to Alex, pleas for her to wake up, to open her eyes, to be okay. Because Kara couldn't survive if her sister wasn't okay.

"Come on, Alex," Kara murmured, words slurred by fatigue. "You gotta wake up, I need you."

She fell asleep whispering, hand fitted around Alex's, sitting at her side.

iii.

Alex lurched awake with a jolt, gaze tearing across her surroundings, some foreign energy alive and buzzing in her chest. It was gone before she could even pinpoint it, dissipating the moment warm hands engulfed her own and the sound of her sister's voice cracked through the clouds in Alex's brain.

"Hey, Alex," Kara whispered, straightening up in her seat and leaning closer. "Hey, you're okay. It's okay."

"How long was I out?"

"Three days," Kara said, nearly choking on the words. "How-how much do you remember?"

"The helicopter, the lightning," she waved her hands and smiled. "Most of it."

"I'm s—"

"No way. I'm cutting you off. This wasn't your fault, Kara."

The blonde opened her mouth to protest but Alex cut her off again. "If it weren't for you I would be dead, okay? Remember that."

"Okay, but still, I didn't mean—" Alex put her hand over Kara's mouth, laughing. "Hey!" Kara murmured behind her sister's grasp, poking her tongue out to lick Alex's fingers.

"Ew!" Alex screamed and pulled her hand away, watching as a smug smile appeared across Kara's cheeks. "You're gross."

"I'm effective."

"Yeah, well, you also seem tired and hungry. Have you been here the whole three days?"

Kara shrugged.

"That's a yes," Alex said as doctors began to enter the room. "Go home—sleep a little, grab something to eat, make sure you still have a job at CatCo," she grinned. "I'm joking," she said in response to the sudden concern that splashed across Kara's face. "But go, take care of yourself. I'll still be here, I'm sure." She gave a glare at the medical equipment attached to her body and a smile fell over Kara's lips in response.

"Are you sure?"

Alex nodded. "Very."

"I love you," Kara said as she stood and squeezed her sister's hand.

"I love you, too."

iv.

Lightning. It was the first thing on Alex's mind when her eyes bolted open in the DEO medical corridor, alone in her room. Void of doctors and light, except… except for the silvery blue flickers of lightning spilling from her fingertips like water from a river. The electricity quivered, static and snapping, before it popped and the room was flooded in darkness with the exception of humming medical equipment and the stars shining beyond her window.

Alex sat wide-eyed, breath hitched in her throat as her gaze shot around the room and her mind scrambled. Her fingers tousled the contents scattered across her bedside table, knocking over a glass of water in her attempt to find her phone. When her hand finally met the device a sigh of relief parted her lips and Alex dialed Kara's number without thought. It was instinct. It was security. It was habit.

"Alex?" Kara's tired voice filled her ear.

Alex swallowed and closed her eyes, tears slipped from the corners. "Kara? Kara, I need you to get here as fast as you can. Something's wrong."

v.

It took five minutes for Kara to launch herself from bed, change, and fly over to the DEO. The wind became abrasive at her top speed and she dipped into the building gratefully edged into view, skin pink and hair a mess. She followed the memorized path to the medical unit, well known from repeated exposure.

Kara furrowed her brows when she approached Alex's room and found it nearly empty—there were no doctors bustling around the brunette, yelling and prodding like they usually did when something was wrong and health was at risk.

Instead, it was still, and Kara felt her breath catch in her throat.

Only Alex was in the room, covered in the white sheets as she had been earlier, but now her eyes were set open, assertive and fearful.

"Alex, what happened?" Kara asked, dropping into the seat beside Alex's bed. "What's wrong? Are you hurt?" The blonde scrutinized her sister, examining for skeletal cracks with her x-ray vision and listening with her super hearing. The only abnormalities her senses documented were a thundering elevated heartrate and quick, short gasps of breath that rattled from the agent's lungs.

"Alex, say something, you're scaring me."

Another trembling breath slipped from Alex. "I-I'm scaring myself…"

"What does that mean?" Kara whispered, slipping her hand around Alex's.

The brunette yanked her palm away and pretended not to see the hurt that flashed across her sister's features. "I… it's—it's not you. I—I don't want to hurt you. It's easier for me to—to show you, than to explain." Her voice shook.

Before Kara could respond, Alex had raised her hands, contorted her fingers slightly above the blankets. Within seconds light flared from her skin, strong and white. It crackled. She curled her fingers closed and the electricity vanished.

Alex kept her gaze down, until the silence stretched between them bore a hole of worry in her stomach so painful she couldn't ignore it any longer. She peeked at her sister, looking up through dark lashes to find Kara's face twisted in an expression of shock and awe, mouth open, eyes gawking.

She started to talk and faltered with her words. "That… that." Alex felt her heart cracking, tears threatening to streak her cheeks.

Kara's face cracked into a smile and she shook her head. "That was awesome," she declared, meeting Alex's eyes and watching as the brunette's gaze shifted from worry to confusion to relief.

"It…wait, really?"

"Absolutely." Kara grinned and took Alex's hand. "You won't hurt me."

Alex tried to pull loose. "I might by mistake. I don't have a lot of control. You—you don't know. You can't be sure."

"Well that didn't stop you from holding my hand when I first came here and could literally snap your bones on accident."

Alex shrugged. "I trusted you. It was worth the risk."

"And I trust you. You're worth the risk, too." Kara said and brought their linked fingers up to her face. She pressed a kiss to the back of Alex's hand before brushing a strand of hair off the brunette's face. "You are going to be just fine."

vi.

"Not quite, let's go again," Kara said three weeks later, extending a hand to Alex who had flopped onto the padded ground a moment earlier in the green k training room with the dial just slightly turned up.

"Karaaa," she groaned, but grasped the hand and let herself be pulled up.

"One more time, you're so close."

"No. I'm not," Alex muttered.

"Yes you are, just concentrate. Aim for the target."

Alex rolled her eyes, but set her right leg back, getting in stance and turning her fingers toward the replica human figure across the room. She took a deep breath in hopes of regaining control before what felt like her twenty thousandth attempt.

The lightning first spread from her fingertips toward the target, but then the electricity flared out reaching the figure while simultaneously snapping against Kara's abdomen. "Ow! Shit!" the blonde murmured, jumping back when the lightning released her from its grasp. She stumbled for a moment, wrapping a loose arm around her waist, gaze trained down until the slamming of the door yanked her attention.

Alex was gone.

Kara followed the sound of footsteps down the hall and when she lost them she used her super hearing to find Alex's beating heart two flights of stairs below and one corridor to the left. The brunette sunk against the floor, back pressed into a corner of the vacant wing.

"Hey," Kara said softly, dropping into a sitting position across the hall from Alex so their feet almost touched.

"Go away," Alex muttered, voice tinged with tears and face hidden in her hands. "I'm just gonna hurt you more."

Kara moved from her position and Alex's heart jerked painfully until the blonde slide next to her sister and tugged her into her arms. "Never," Kara whispered and pressed a kiss into Alex's hair. "I was only able to do this—to cope with powers, to live on Earth, to do anything here—because of you. And I am not abandoning you now. Nothing in the universe could make that happen. I have you and you have me. Always."

"I can't do it," Alex whispered and squeezed her fingers tightly around Kara's cape as she held her close.

"Of course you can. Now get up, we're not leaving until you get it right because my Alex doesn't give up and you're still my Alex."

The agent took one last moment held tight in her sister's arms, warm and safe, before nodding. "Okay," she whispered. Kara wiped Alex's eyes and stood up, extending another hand to the brunette.

Alex sniffled and followed her sister's lead. A smile spread across her red cheeks. "Let's do this."

"Aaaand she's back," Kara said, grinning and looping her arm through Alex's.

vii.

"I need you both out there, stat! The aliens are too strong for the unit we sent out, they're losing ground." J'onn yelled through the DEO comms to Kara and Alex as soon as he got word of an alien group wreaking havoc across National City, two months after Alex first gained her electrical abilities.

"You ready for this?" Kara asked, grinning at her sister outside the DEO headquarters. "It's your first alien ambush with powers! Look at you growing up."

"You're maybe a little too enthusiastic about this," Alex said with a laugh as Kara grabbed her and launched them into the sky.

They landed in the center of the fight, surrounded by the DEO agents who'd been engaged in battle for the past hour. The majority of aliens had been rendered unconscious, lay scattered across the city street but the remaining two were the largest and had single handedly carried on the fight, the obvious leaders of the group. Their blue, rough skin stretched across massive frames twenty feet tall as they flung agents to the ground.

With each collision the cracking of bone filled Kara's ears. One alien propelled itself into the sky with powerful bounds, each leap splintering the asphalt as it moved toward a more populated area where families were gathered and spending the afternoon, oblivious to the impending alien attack.

"Alex, I'll get that one. You stay here and take care of the first one," Supergirl yelled before disappearing into the distance and leaving Alex alone. The brunette turned around, frozen for a moment, watching as the creature ripped a hundred year old tree from the ground and snapped it in half before swinging it at buildings.

The bigger they are, the harder they fall. From somewhere deep inside came the once forgotten words her soccer coach used to remind her of back in high school, when she was younger and playing up with older, bigger kids. Play to your advantage, Alex he'd tell her turn it around.

Alex took a deep, shuddery breath. She could do it, she could do it, she could do it.

"Go," she screamed to the DEO agents, watching as they took advantage of the distraction to retreat.

The alien made a horrible yell as it tossed the tree and swept with its bare hands. Alex sprinted closer, until it was just in range and sent sparks from her fingers. They crackled and fizzled out.

The creature faced her, distracted from the civilians it'd been terrorizing. A laugh bubbled from within the alien. "You stupid human," it growled and took a slow step closer, its form blocked out all sunlight reaching Alex.

With a racing heart and shaking hands she tried again but the lightning just snapped and disappeared. Kara floated in from the distance, the other alien unconscious some blocks away.

"Supergirl, get him," Alex whispered, knowing her sister would be able to hear.

"No," Kara screamed back, switching direction as she heard the voice of a crying kid below her. "Remember what we practiced. Breathe. You can do it."

As Kara was occupied with flying the lost child away from the area the last alien turned toward the blonde, looming over the red cape and preparing to slam Supergirl and the kid against the ground.

"Stop!" Alex yelled as she raised her hands and bolts of lightning shot from her palms, colliding with the blue mass and sending the creature crashing backward away from Kara. His muscles contracted and he lay motionless on the ground as DEO agents surrounded him, applying restraints.

Alex collapsed, falling backward into a sitting position in the middle of the street, eyes wide and lips curling to resemble a smile as her hands met the concrete and the scene filled her sight.

The child in Kara's arms looked around before making eye contact with Supergirl. "She just saved us," the little girl whispered, gaze shiny and bright as she peered at Alex.

"Yeah," Kara said with a smile. "She did."

viii.

"You were amazing," Kara said as Alex entered the blonde's apartment that night.

Alex just grinned and set a box of pizza on the counter. Kara whipped around from the couch. "You just got even more amazing," she declared, floating in all her excitement and using super speed to grab a slice and shove it into her mouth. "How do you feel?" the blonde asked through a mouthful of food.

"Really good." Alex beamed and grabbed her own piece. "Like I can do anything. I could go again right now."

Kara laughed. "Well, maybe you should rest a little before next time."

"Nah," Alex shook her head. "I'm learning from you."

The blonde rolled her eyes with a smile. "You were incredible, Alex, really," Kara said and pulled her sister into a hug before returning to the couch with the box of pizza in hand. "Now come sit with me," she patted the seat beside her with her elbow. "We've have lots of TV to catch up on and lots to talk about."

Alex smiled and sat next to Kara, pulling a knee toward her chest and leaning against her sister as they flicked on the television.

"I'm proud of you," Kara whispered after some time passed and Alex's head rested sleepily on her shoulder, eyes fluttering closed.

Alex smiled. "That's my line."

Kara shrugged and ran a hand over Alex's hair. "Sharing is caring, and it's true. You were really phenomenal."

"Thanks, Kara," Alex murmured and snuggled beneath the blanket. "I couldn't have done it without you."

"Ditto," Kara said. "I guess we need each other."

Alex curled her hand around Kara's. "I wouldn't want it any other way."