Welcome to the first of hopefully many Supergirl one shots! I'd love to hear your thoughts about my stories and prompts are always welcome!

This AU is set during 2x21 and 2x22. As Alex jumps off the DEO building, she's shot by a Daxamite but tries to hide it from everyone despite her condition worsening.

Note: I've skipped a few parts of the story, most notably the Sanvers proposal at the end, but I could always add that as another chapter if it's something you'd like to read, (even though this would no longer be a one shot). Also, Kara is dating Lena.

Alex knows that her sister will catch her.

There's no hesitation in her mind when she realises that there's only one way to escape the Daxamite invaders that are beginning to overrun the DEO.

She has complete faith as she jumps off the side of the building because Kara always has her back.

She jumps and twists in the air, facing her enemy before firing one last shot.

What she doesn't expect is for one of their shots to glance her stomach just a fraction of a second before she disappears behind the side of the building.

Splitting pain burns through her muscles, aches to her bones as she plummets through the air. She can't breathe, can't think as she falls. Every fibre of her being is focused on the throbbing in her torso.

And then she feels arms wrap around her, holding her close, just as she knew they would.

She exhales sharply, but not in relief, though Kara doesn't know that.

She blinks to fight back the tears that spring to her eyes as her hands rest over the injured area, her heart racing. It hurts to touch, hurts to think about and Alex presses her face into Kara's shoulder so that her sister can't see when she scrunches it, bites down hard on her lip to stop a scream from escaping.

When Kara sets her down at the alien bar, she fights to stand up straight, refusing to let the pain beat her. She can't show any weakness, especially when there is so much at stake, especially not in front of the president.

She's thankful that the Daxamites use blasters and not bullets, otherwise blood would be soaking her skin and drenching her clothes, and then she wouldn't be able to help Kara.

She tries her best to hide the pain, although she can tell from the looks that Maggie keeps giving her that the detective knows that something is wrong. She doesn't give her girlfriend the opportunity to ask her about it, though, and she barely has time to think about it herself, as hard as it is to forget.

Kara prepares to leave with Lillian, which everyone knows is a bad idea, but Alex knows that she would be doing the same if it were Maggie.

Through slightly blurred vision, Alex begs her sister to be quicker than her, faster than the positron cannon. She grasps Kara's arm in an attempt to keep herself steady, pulls her into a hug when she realises that the pain is getting worse.

Kara's parting words to Alex are something about a speeding bullet and as much as Alex tries to hang onto them, to focus on her sister's voice and overlook the irony, the words all blend into one, so she just nods and forces a small smile.

On the journey to the DEO, Alex remains silent and stares out of the window, trying not to make eye contact with Maggie. She visibly flinches every time they hit a bump in the road or round a corner because her muscles tense and send fresh flashes of pain surging through her body, but Maggie knows that Alex's silence means that she doesn't want to talk about whatever is bothering her so she nips her cheek between her teeth to stop herself from asking.

"She'll be fine, y'know," she says instead. "She'll be back."

Both women know that this isn't the only thing that's bothering Alex, but neither says anything else for the rest of the journey.

Alex bites down hard on her lip as she jumps into the vent, fighting the urge to cry out in pain. She grunts instead, making it sound like a natural reaction to the impact. She can taste metal in her mouth as drops of blood seep into it from her lip, but it's the least of her worries.

She just about manages to keep her voice steady as she acknowledges the president's commands.

But she can't fire, not yet.

She clings to the trigger, placing most of her weight against it in an attempt to alleviate some of the intense pain that still seems to be getting worse and worse with every passing second.

Sweat begins to form against Alex's hairline and she gingerly raises an arm to wipe it away.

And then the building rumbles and the canon is gone.

Alex looks at Maggie, her eyes filled with panic. She lets go of the trigger, but her next sudden movement sends pain shooting up her side.

She stumbles towards Maggie, her knees giving way beneath her as the pain worsens, burns deeper.

The detective reacts quickly, catching Alex before she can hit the ground. She lowers her gently so that the agent's back is resting against her legs.

"Hey, hey" Maggie coos, concern plastered across her features. "What's the matter, Alex? What's wrong?"

Alex sucks in a deep breath even though it's becoming a painful chore, more and more agonising with each rise and fall of her diaphragm. Her eyes suddenly overflow with tears as her breathing becomes smaller and more ragged. Despite her shaking hands, she manages to grab the hem of her shirt and pull it up enough to reveal a mass of purple covering the front of her body.

Through blurred vision, she sees Maggie's face full of horror, her usually calm, kind brown eyes filled with fear and panic.

"Oh my God, Alex," she almost shouts, unsure of what to do to ease her girlfriend's pain. Using the comms Alex had given her, she barks orders down the line to get the medical team down there.

"Stay with me, babe," she says soothingly, stroking Alex's hair and pressing kisses to her cheek and forehead.

Alex's eyes begin to droop closed, heavy from fighting the pain, fighting the Daxamites, fighting to stay awake.

Though she never stops battling, never stops wanting to overcome the fatigue to help her sister, to help Maggie to fight the Daxamites, her body takes over and begins to shut down and the last thing she thinks she hears is Maggie calling her name over and over again.

Alex's eyes flutter open.

The bright light surrounding her slowly pales until everything comes into focus and she eventually figures out where she is.

She tears her eyes from the med bay ceiling to find Maggie and Kara sat on either side of her bed, their heads resting against the soft mattress, arms outstretched over Alex's legs so that their hands grasp onto one another as they sleep.

That can't be comfortable, Alex thinks until she tries to reposition herself, sending pain flaring across her middle and realising the real meaning of discomfort.

The slight jolt and gasp from Alex rouses Maggie and Kara. Their faces light up when they see Alex smiling down at them.

"Oh Alex," Kara says, her voice catching in her throat at her eyes begin to fill with tears. "We thought we'd lost you."

Alex shakes her head, noticing how red and blotchy Kara's cheeks are as well as the puffiness that surrounds her normally striking eyes. "I'd never go anywhere without either of you."

"What happened, Alex?" Maggie asks, her face showing her concern.

Alex sucks in a deep breath, knowing that neither woman is going to like the answer.

"A Daxamite shot me as I jumped off the DEO," she says quickly and quietly, unable to look either Maggie or Kara in the eye.

"You jumped off the DEO?" Maggie almost shouts, eyes wide.

"Kara caught me, she knew it was coming," Alex says, glancing up at the now frowning detective.

"Wait, so all that time I carried you, all that time at the bar you were hiding it from us?" Kara says, pacing. She doesn't wait for her sister's answer because she already knows what it is. "Why didn't you say anything?"

Alex watches her sister as she perches by her legs at the edge of the bed. Maggie, meanwhile, stands with her arms folded, expression unreadable.

"I didn't want to add more pressure or stress to the situation." Alex keeps it short, although she knows she won't hear the end of it.

"But Alex, this is serious. You could have died. Doctor Hamilton says that had the shot hit you full on, you might not be here right now." Maggie can't stop her lip from quivering as she speaks, as Hamilton's words flood her head and fill her body with the same sense of dread as they did the first time they were spoken. "I can't live without you, Alex." She takes Alex's hand and feels the agent squeeze it back, letting her know that she's still here.

"I should have noticed," Kara says. "Rao, I'm such a terrible sister, I should have noticed. When I caught you I could hear your heart racing but I thought it was because you were falling. I'm so sorry, Alex." She shuffles off the bed, looks down at the ground, unable to look her sister in the eye, hands resting by her side.

"No, Kara," Alex begins, her voice steely and commanding. "Do not blame yourself. You had so much to deal with already, you were worried about Lena and Mon-El and I didn't need to add to that list, didn't need to distract you or burden you with more stress. You had my back and I still wanted to have yours."

Kara tears her eyes from the ground to meet Alex's soft brown ones that are looking back at her. She takes in her sister and, even if Lena has to debrief J'onn about the lead diffuser and Mon-El's gone because of it, she's immediately grateful that she's with her.

Because Alex has always been there and Kara needs her by her side, wouldn't be the person she is without her.

"You're never a burden, Alex. Please know that," Kara says, stroking Alex's hair. "I'm always here for you, whenever you need me. I'll be with you every second until you're better."

Alex smiles at her little sister, the usually bubby blonde who currently has the weight of the world pressing on her shoulders, and feels proud of what she's achieved, of how she stands up in the face of danger and fights for everyone before herself.

It's only then that she realises that Maggie has been quiet for a few minutes.

"Maggie?" Alex says softly, catching her girlfriend's hand.

"I get why you didn't tell Kara," the detective snivels. "But why not tell me?"

Alex doesn't hesitate in her response. "Because I wanted to protect you, and you'd never have let me help."

"Damn right I wouldn't," Maggie says, causing Alex to laugh.

Maggie's shoulders visibly loosen at the sound.

"Come on," Alex says, holding out an arm to each woman on either side of her bed. "Come and have yourself an Alex sandwich."

Kara and Maggie do as Alex says, careful not to touch her anywhere near her stomach where the bruising was still purple.

"Wait, how are Lena and Mon-El?" Alex asks.

Kara's face falls. "The only way to stop the invasion was to fill the air with lead."

Alex pieces together the rest of the unspoken sentence. "So he's gone?"

Kara and Maggie nod solemnly.

"I'm sorry, Kara. I know you'd become good friends."

Kara nods her thanks but quickly changes the subject. "So when Maggie, Lena and I get you out of here, what film do you want to watch?"

Alex smiles at the normality of the question. "Something with lots of guns and battles."

Kara and Maggie laugh. Alex joins in too before she finds herself in the middle of another group hug, and that's exactly how Lena finds them.

/

A few days later, Alex is allowed home.

I deserve to be, she thinks, after doing everything Hamilton and Maggie had demanded of her.

Kara refuses to let her big sister out of her sight and constantly throws questions at her, checking she's all right, checking that she's comfortable, checking what pizza toppings she wants.

Lena plants herself to Kara's right, offering Alex and Maggie some pizza before giving Kara a whole box to herself.

"So what was the president like?" The CEO asks, ripping off a bit of her slice before placing it delicately into her mouth.

"Amazing, as you'd expect," comes Kara's muffled reply, her own mouth stuffed with dough. She gulps it down. "But not as amazing as you."

Behind Kara, Alex and Maggie start giggling and making vomit noises at the Kryptonian's cheesy remark.

Lena laughs heartily while Kara glares good-naturedly at Alex and Maggie, who proceed to laugh even more when Kara puts on her best pout.

When they finally recover, Kara grabs her last slice of pizza and holds it in the air in front of her.

"To Alex," she says.

The three women around her hold their slices aloft and tap them against Kara's.

"And to always having each other's backs."