Disclaimer: I do not own DC Comics or the CW TV shows Arrow, The Flash, Legends of Tomorrow, Supergirl or any other characters or elements pertaining to the mentioned franchises.

Kara, Mon-El, Barry and Cisco were in the ship, flying in deep, dark space as Cisco laughed. "Wow, this is a dream come true."

"You've never flown in space before, Cisco?" Mon-El asked.

"No." Cisco said.

"I've almost forgotten how beautiful it is." Kara admitted.

"Me too." Mon-El nodded. The console then bleeped as Mon-El took a look. "We're coming up on it."

The ship stopped traveling in lightspeed as there was a city in a dome on a meteorite, with green veins on the surface as Kara took a closer look. "There it is."

Suddenly, from the city shined bright light, causing for the ship to stop as Kara, Mon-El, Cisco and Barry grunted.

"It's a tractor beam." Mon-El realized as the systems in the ship beeped rapidly.

"Everything's locked up." Kara said.

"Thrusters, roll, yaw and pitch, nothing's responding." Mon-El checked the systems.

"Getting caught in tractor beam is never good in any sci-fi film." Cisco grumbled.

"What if we're not us?" An idea hit Kara.

"What?" Mon-El, Cisco and Barry stared.

"This ship can turn into other things." Kara explained.

"They don't want any uninvited visitors but they don't have to know we're uninvited." Cisco realized.

"Brainy's gonna be so sad he missed this." Mon-El chuckled as the ship turned into an asteroid that wasn't pulled towards the dome with the tractor beam but was still heading towards it.

DEO

"Agent Schott, any word from Supergirl or the Flash?" J'onn asked.

"No but we expected that, they're on the dark side, which means they're probably scraping off a nice chunk of space rock of a much larger piece of space rock any minute." Winn replied.

"I need to know any second they're on their way back." J'onn ordered.

Alex's apartment

Alex, Henry and Ruby were watching TV as Ruby was staring blankly, while Alex sat next to her on the couch with a bowl of popcorn in her hand.

"Now, Supergirl and the Flash are up there right now on a mission to find a substance that's gonna fix your Mom." Alex assured her.

"There's so much nothing." Ruby said while watching the documentary about space. "What if they don't make it back in time?"

"Ruby, if anyone can save your Mom, it's Supergirl and the Flash, the fastest man alive. Don't worry." Henry held her shoulder.

"Hey, you know what? Why don't we get out of here?" Alex turned off the TV. "I just happen to know where there is a wicked ice cream truck. And, I mean, all the toppings."

"That's all I need right now." Ruby smiled.

"Then let's go." Henry ordered as they got up from the couch. "I'll call Oliver and Laurel, maybe they could come with us too if you don't mind."

"Sure." Ruby nodded.

National City

Alex, Henry, Sara, Ruby, Oliver, Laurel, holding their daughter on a baby carriage were walking down the park as Sara, Henry, Alex and Ruby were eating the ice cream

"I could definitely be an astronaut." Ruby said.

"Mmm, I could see that." Alex nodded. "You know, once you get past your motion sickness thing, I think you'd be golden."

"That's funny 'cause I never got motion sickness until you started driving me around." Ruby cracked as everyone snickered.

"Maybe Uncle Henry could start driving you around, instead." Laurel said.

"Come on, give me a break." Alex mocked before they approached a clothes shop as Alex put a hat on Ruby's head. "Alright, look, let me see."

"That's cute." Oliver said.

Alex then tried on sunglasses before she noticed in the mirror someone behind her as she put down the glasses and in that moment, everyone else, aside from Ruby, noticed that, too.

"Ruby, why don't you and Uncle Henry go buy some sodas, we'll pay for the hat and glasses, OK?" Sara ordered as Henry and Ruby walked away and as everyone else turned to the man behind Alex, they noticed a gun in his hand.

"Gun!" Alex cried out as everyone crouched in panic, while Alex took cover behind the shop before the man threw a small device that was blinking blue light across the pavement and beeping. Alex rushed to the nearby hot coal disposal and threw the device inside. "Everybody get back!"

From the disposal went off muffled explosion.

"Who the hell was that?" Oliver demanded.

Argo City

The ship landed in forest in the dome as Kara, Mon-El, Barry and Cisco went out. "There's an entire city here, how did we miss this?" Kara demanded.

"We're on our own." Mon-El said.

"And powerless. At least us." Kara pointed out before turning to Barry and Cisco.

"Should have figured, without the yellow sun." Cisco said before Mon-El used his ring and showed a hologram of the city.

"Looks like the black rock is about a mile into the city." Mon-El said.

Kara nodded. "We better get moving before they…"

"Look out!" Barry pushed everyone forward as above them something was firing lasers on them as they went deeper into the city.

"What the hell was that?" Cisco demanded.

"We have other problems." Mon-El said as they noticed that the people around them were staring at the heroes.

"They seem human." Kara said.

"Guys, I think we need to change our clothes, we don't exactly fit in here." Barry pointed out.

"Good idea." Kara nodded as they approached a nearby shop, taking some capes before noticing a sick boy with a life support attached to his nose.

"Poor boy." Barry whispered as everyone looked at him in sympathy.

"Let's go." Kara ordered.

"You OK?" Mon-El asked.

"Yeah, just thinking how ironic this is." Kara chuckled. "Donning disguises across the solar system seems to be my karma."

"It's not like people like you or Diana have another choice back on Earth. If people knew who you really are, they'd see you differently." Barry pointed out.

"He's right, it's necessary for survival." Mon-El nodded.

"So is Kara Danvers. I just wish my day-to-day life didn't have to have a disguise." Kara sighed. "It's exhausting."

"In the future, I just live in the open. All Legionnaires do." Mon-El pointed out. "There's no secret identity, no disguises, 24/7, I'm just me, Mon-El from the Legion of Superheroes. And it's still exhausting."

"I guess this life will always have its pros and cons." Cisco pointed out.

"I guess you're right." Kara nodded as Mon-El looked at the map of the city. "We're getting close."

DEO

"This place is intense." Ruby said as she with Alex, Oliver, Laurel, Henry and Sara entered the headquarters.

"Ruby, why don't you go with Uncle Henry for a moment, he can show you some work he does here, I need to talk with my friends here, OK?" Alex ordered as Henry accompanied Ruby into a conference room. "Someone's trying to kill me." She told J'onn and Winn.

"Things were not chill." Winn quipped.

"You sure you were the target?" J'onn asked as they were walking down the stairs.

Alex scoffed. "100%. Guys, this is really bad, I can't have some psycho, who's trying to murder me, out there, while we're taking care of Ruby."

"Don't worry, we won't let anything happen to her." Sara assured her.

"Well, if they'd attack you out in the open, it means that someone wants you dead. Any ideas?" Oliver asked.

"Where do we start?" Winn snorted as he looked at the computer. "OK, well, there's Griggs, the Hellgramite, Hannibal…"

"Look, the Hellgramite and Griggs have been in containment. So, that's a 'no'." Alex said.

"Hannibal, we've deported after Daxamite invasion." J'onn said.

"Wait, it doesn't have to be someone from your time here." Oliver pointed out.

"What do you mean?" Winn and Alex and J'onn turned to him.

"I've had my experience with people from my past before I took on the hood, that have been trying to kill me." Oliver said.

"Is there anyone from before you became an agent, who may have an axe to grind with you?" Laurel asked.

"Mr. Queen and Miss Lance have a point." J'onn nodded. "Is that anyone from your past, who may have threatened you before?"

There was one person Alex could think of. "Pull up Ron Collins."

"Ronald Collins. Let's see." Winn pulled out a profile. "Age 56, recently made parole after six failed attempts. Wow. Let's see, he was in for…"

"First-degree murder. I should know, he was my first arrest." Alex said.

"I'm sorry, that would have made you… that would have made you seventeen, when you arrested him." Winn said as Alex gave him a look. "Yeah… that tracks."

"He lived his whole life in Midvale and then he moves to National City after he was released from prison?" Alex pointed out.

"A lot of trouble to go for, because of a ten-year old grudge." Oliver said. "But then, revenge is a powerful motivator."

"He moved within six blocks of your apartment." J'onn nodded.

"OK, I ruined his life, he's trying to ruin mine, that's him." Alex said. "I'll pay him a visit."

Argo City

"The Black Rock is definitely in here." Mon-El said

"Let's go." Kara ordered. They approached the post before Kara looked at the wall with Kryptonian symbols carved on it.

"What is it?" Cisco asked.

"And on Earth, the soul is lost in destruction. May their flames forever burn in Rao's light." Kara read. "It's a Kryptonian memorial."

"Wait, how is that even possible?" Barry demanded. "I thought Krypton was gone."

"It is." Kara nodded before looking around and recognizing the landscape, not wanting to admit it to herself at first. "This is Argo."

Mon-El gasped before they were surrounded by drones. "Don't move. Identify yourselves." Cisco and Barry were about to attack the drones before a female voice called out.

"Stand down, caretakers." The woman in blue dress said as she showed up, while Kara widened her eyes in disbelief.

"Mom."

"Mom?" Barry and Cisco asked simultaneously.

"Kara…" Alura approached Kara and hugged her tightly. "Is that you?"

She sobbed and let the hug sink in before letting go. "How are you alive?" Kara demanded.

"Your father created a shield to protect Argo, when Krypton exploded." Alura explained. "We would never have sent you away, if we had know it'd work. I thought you were dead."

Kara sniffled, while Barry, Cisco and Mon-El looked at her in sympathy, Barry and Mon-El mourning for their own parents, while Cisco was grieving for his brother.

"I don't understand, I saw your pod get knocked into the Phantom Zone." Alura said, looking at Kara confused.

"I… I was stuck there for years but somehow, my pod got loose and I fell to Earth with Kal-El." Kara explained, trying to get a hold of herself as tears were filling her eyes.

"Kal made it, he's alive." Alura smiled.

"He got there first." Kara nodded. "If I had known, if I knew Argo was here, if I knew you were alive, I never would have stopped searching for you."

Alura looked at Kara in sympathy before turning to Mon-El. "I recognize you. The prince of Daxam."

"There is no more Daxam." Mon-El stepped up. "I'm just Mon-El now, ma'am."

"There is no more Krypton either. Only Argo." Alura nodded before turning to Barry and Cisco. "And these two are…"

"Mom, these are my friends, Barry Allen and Cisco Ramon from Earth. Different Earth." Alura scowled. "It's complicated but… they're from another dimension. They're very capable people and good friends."

Alura nodded. "I'm glad Kara has such faith in you to bring you here." Then, she turned to Kara. "If you didn't know I was alive and you weren't searching for me, what brought you here?"

"Earth. Earth is in trouble." Kara explained. "When Krypton exploded, the followers of Yuda Kal sent three pods after me, each with a Worldkiller."

"A Worldkiller?" Alura demanded.

"Two of them are dead but the last one absorbed their powers and she's terrorizing Earth." Barry explained.

"Reign, she's hurting people I love, murdering indiscriminately." Kara said.

"We believe that there may be a substance here that can stop her, once and for all." Cisco said. "That's why we came here."

"Harun-El." Alura realized. "The Black Rock of Yuda Kal."

"You know what it is?" Kara widened her eyes.

"After the fallout, ashes and destruction poisoned the air." Alura explained as they went downstairs, showing them a large stone on a pedestal. "We had nothing to protect us as we hurled through space. The young and the old were the first one to become sick. They struggled in our new atmosphere, their lungs more vulnerable, more weak. But after the fallout passed, the shield, the shield kept our atmosphere more hospitable. It is what your father gave his life for.

There was no more time, Argo was in constant darkness, we were running out of air, we were dying. Your father repurposed his unfinished research to create a livable environment. He believed that the Harun-El could act as a shield for the city and he was right. His legacy keeps our air breathable and shield us from invaders. It keeps us hidden…"

"That's why we didn't detect you in our scans." Mon-El realized. "Why there were no signs of life."

"And why we can't get in touch with Earth." Kara added.

"Cisco, could you breach us out of here if you could?" Barry asked.

"I don't know." Cisco said as he opened a breach before it closed. "OK, at least we know we can get back home in time."

"What is that?" Alura stared.

"Well, you know how I told you how they can travel through dimensions?" Kara asked.

"Amazing." Alura smiled.

"Look, we don't need too much of your Harun-El. Please." Barry begged. "The Earth is at stake."

"It is not mine to give." Alura pointed out. "But I will call a meeting with the High Council."

"Thank you." Kara nodded.

DEO

Ruby was playing with Oliver, Laurel and their daughter, Henry and Sara before Ruby looked sad.

"Do you think I'll get my Mom back, Aunt Laurel?"

"I don't know." Laurel said, holding Ruby's shoulder. "But what I do know, is that Supergirl has the help of the fastest man alive. And if anyone can find a way to save your Mom, it's them. Because if there's one thing the Flash is good at, it's saving people from their dark sides." She said in motherly manner as Ruby seemed a little convinced.

Argo City

"Your friends, the metahumans, how did you meet them?" Alura asked.

Kara sighed as they sat on couch. "Barry… he's a speedster. He's actually so fast that one time, he accidentally ruptured space-time continuum and created a breach and ended up in a different dimension. Our dimension. And… he saved my life." Kara said. "When it was over, I helped him get back home. He's been a good friend to me since then. We've been through a lot together."

"I saw the way you two look at each other." Alura pointed out as Kara flushed. "Are you two…"

"It's… we're trying." Kara admitted. "But…"

"It's not easy, when you two are universes apart." Alura realized as Kara nodded as Alura held her hand. "I'm not going to pretend I understand all of this… multiverse theory but… if you truly care for each other, I'm sure you'll find a way to make it work."

"This place is amazing." Cisco said as he looked around.

"I'm glad for her, actually." Barry said. "For fourteen years, she believed that her home had been destroyed and… knowing that not only a piece of it survived… but her own mother… living a normal life here…" He trailed off, thinking of his father in prison, where he spent fifteen years in misery as Cisco looked at his best friend in sympathy and held his shoulder.

"You're not alone, buddy. You still have us."

Alura and Kara entered the round room as Alura introduced Kara to the council. "Allow me to introduce you to my daughter."

"Kara. Welcome home." Selena, the Dark Priestess in disguise, greeted her.

"Esteemed members of the High Council of Argo City. Thank you for seeing me on such short notice." Kara said.

"Alura is a pillar of our community and a longstanding member of this council." Selena turned to Alura. "We would be remiss in refusing her daughter an audience."

Kara smiled as Alura spoke up. "As you may know, Zor-El and I came up with a plan to save Kara during the dark days before Krypton's destruction. We didn't know that Argo could survive and so we put Kara, our only child, into a pod and we sent her to Earth. It's people took her in, they saved her. And in exchange, she serves the people of her adopted home. She's a hero that embodies our greatest ideals. But unfortunately, Kara was not the only Kryptonian that travelled to Earth."

"A Worldkiller followed." Kara explained.

"You must forgive our skepticism." Jul-Us said. "You've been away a long time. Here on Argo, Worldkillers are the stuff of children's stories."

Kara nodded. "I too, was hesitant to believe that such a thing could be real but I faced it. She is real and she calls herself Reign." Selena, from all members, was listening to Kara with deep intrigue in her story. "I travelled here from across the stars because I could not defeat her, not even with the help of my friends. And Earth is in grave danger."

"An unfortunate situation if true but how can Argo be of help?" Selena inquired.

"Indeed. We are a recovering city." Jul-Us pointed out. "Still limping wounded from the trauma of destruction. We can't communicate outside our protective dome, let alone send troops or aid beyond its border."

"It isn't troops we need." Kara shook her head.

"Then, what is it you seek?" Selena asked.

Kara turned to Alura, who subtly nodded. "A gift… of Harun-El."

All the councilors looked at Kara in surprise.

"You would have us give away our most precious resource, our only lifeline, to an alien species?" Jul-Us demanded.

"The people of Earth share our ideals. They're more like us than you realize." Kara pleaded.

"Or perhaps you've become more like them than you realize." Jul-Us countered.

"With all due respect, councilman, the danger currently facing Earth is of Kryptonian making." Alura pointed out.

"And I need not remind you, Alura, that Krypton is dead." Jul-Us protested. "Argo City is all that remains."

"And yet the sins of Krypton live on in this Worldkiller." Alura argued. "Can you abide this as our legacy?"

"This council does not concern itself with legacy, only survival." Jul-Us said.

"And what is the point of survival, if there's no soul to save?" Alura demanded.

"I agree with Jul-Us." Selena turned to him. "His position is wise and thoughtful."

Kara sighed deeply. "Your point is well made that Krypton is dead but its legacy lives on. For good and ill. My own mother sentenced prisoners to Fort Rozz. Prisoners, who broke free and took their anger out on Earth, many of whom we're still trying to apprehend.

There are people on Earth, who work every day to solve mistakes of Krypton's past. People, who are trying to make Earth fairer or just better. These people dedicate their lives to this work and some have even given their lives to it. This planet, these people, they took me in. An alien immigrant from a world they knew nothing about. A world, whose legacy threatened their way of life and their safety, again and again and again.

And now, they deserve it in kind because their very existence is threatened by this Worldkiller of Kryptonian making. My mother tells me that Argo City has changed, that it has learned from the mistakes of Krypton's past. So, I beg you. Give us the gift of Harun-El. We don't need very much and this bit of charity, it will save Earth." Kara finished.

"Well said, Kara Zor-El." Jul-Us pointed out. "But my concern is for those of us you left behind. I'm afraid we cannot spare the Harun-El. Who votes with me?" A few of the council members raised their hands.

"And those, who believe we should help the people of Earth in their time of need?" Alura asked as the remaining council members, save for Selena, raised their hands, leaving Selena with the deciding vote. "And how do you vote, Selena?"

"If this Reign is as strong as you say she is, are you sure this plan will work?" Selena asked.

"I am." Kara nodded.

"We will give you what you seek." Selena said as Kara nodded gratefully.

"Thank you."

Alura, Selena and some of the people of Argo accompanied Kara, Mon-El, Barry and Cisco to the ship as Selena handed Kara the pouch of Harun-El.

"My daughter is lucky to have loyal friends like you, Barry Allen and Cisco Ramon of Earth." Alura said, turning to them.

"So are we."

"Anything for her." Barry and Cisco nodded.

"Now, go save your friend." Alura ordered as Cisco opened a breach.

The rest of the subplot with the alien attacking Alex would have ended up pretty much the same way before you ask me.

So, what do you guys think?

Please review and let me know if you have been enjoying this and want for me to continue.