Ok, so this is gonna be slightly AU with a handful of OC's and the timeline's slightly different to the show. But why not give it a shot, hey?
Just to let you know, I have given Gus (Pulse) the last name Noble because I couldn't find it anywhere.
Disclaimer; I own nothing familiar.

The Mutant Underground Headquarters had never really been a place for children to spend long periods of time. However for four very unique girls, it became a home from the moment they were born. They were all born within a week of each other with Aurora Diaz being the eldest having been born on the 1st of September 2013. Her best friend Evanna was next being born on the 4th and only 3 minutes older than her twin Rosie. Rosie's best friend, Imogen, was born on the 7th making her the youngest of the quartet. Mutant abilities. That was something the girls were used to as well, not only had they grown up around people with powers but they had their own, their own which were stronger than anything anyone else had ever seen. Aurora could manipulate nature, ranging from plants to weather to simpler animals while her best friend could manipulate atoms (although not very well yet), tearing apart objects or lifting the beds when playing the floor is lava. Rosie could manipulate water and fire, creating and dousing flame before making lakes appear from nowhere. Imogen had power over biological creatures ranging from bacteria to elephants. In short the girls powers were nothing far from terrifying.

Night fell over the abandoned bank that proved sanctuary to so many mutants but there was no rest yet for John, Clarice, Marcos, Lorna or Adaline who had all just been told about a young mutant fugitive on the run from the cops, "I'll stay with the girls," offered Adaline Strucker-Noble as the others all grabbed jackets preparing to face the rain hammering the world, "They need to get to bed anyways, it's only practical," she reasoned with her friends who rolled their eyes knowing that she just wanted to avoid the cold, Adaline may have been a Marine but she really had no tolerance for the cold. Almost 2 hours had passed before the four had found the fugitive, she had been hiding in a warehouse when the cops found them and a gunfight started, the young fugitive hiding herself as they made a run for the car. Marcos was shot leading o Lorna attacking and being arrested.

Nearly 3 hours passed before anyone came towards Lorna who was being held in a clearly temporary cell, her powers were uninhibited and the cuffs were plastic zip ties. The man approached the cell,
"Ms. Dane. My name is Reed Strucker." Lorna narrowed her eyes at the man, he was the man who had caused Ada years of locking herself away from anyone,
"This is my associate, Carla Jackson -" Lorna had enough of playing calm,
"I'd offer you a seat, but..." she motioned around the empty cell which held nothing but her inside,
"You're accused of the attempted murder of two police officers. That plus the enhanced sentencing due to the use of your mutant abilities-" Reed was interrupted by Lorna who rolled her eyes,
"Equals I'm screwed! Yeah. I got that part." Lorna's eyes turned cold as she glared at the man, hating every bone within his body.,
"Look all I know is that I was walkin' home when these cops shot at me." Lorna lied with a shrug of her shoulders, Reed approached the door to the cell,
"Come on, Ms. Dane. You and I both know that you and your associates in the Mutant Underground have aided and abetted dozens, if not hundreds, of fugitives," Lorna couldn't help but smirk as her friends father entered her cell despite the warning of his associate,
"Believe it or not, I'm trying to help you. These are serious charges, attempted murder -" Lorna twisted her had slightly, the man cried out slightly in pain as Lorna messed with screws in his knee,
"Those screws in your knee? An old sports injury? If I wanted to, I could pull out those screws and show you some attempted murder. If I wanted those cops dead, they'd be dead." Lorna dropped her hand making Reed lift a piece of paper from his file and show it to Lorna,
"There's a factor that you may not be aware of." Lorna's eyes widened as she looked at the piece of paper,
"I'm gonna ask the court to assign you a lawyer, okay? You've got a big decision to make, Ms. Dane." Reed stepped back from Lorna who was shaking, he left the room with her screaming causing the lights and a mirror to shatter,
"Just think it over." Reed said before leaving the room followed by his associate.

Fourteen hours passed before John, Marcos and Clarice arrived back at the HQ with the fugitive who they'd found out was called Natalie. The four headed into the building where Sage took Natalie and the others headed into an empty office, John began putting a patch over the bullet wound on Marcos' arm when Ada came in,
"What happened? Where's Lorna?" John spoke,
"We got attacked, she got grabbed." Ada watched Clarice pace the room, Ada's mind was spinning, her marine training telling her to keep cool while her heart was screaming for her to rescue her friend.
"Ada!" Came a shout from John, she looked up to see that the others had left the room and were stood watching a news report, Ada came into the tech room and began watching with them
"Yes, and as we have reported, breaking news on the mutant attack at Belleview High. We believe two young mutants to be responsible for the destruction. We've also heard that Federal authorities will be getting involved." Adeline's eyes went dark as she heard the report,
"What was the school?" She asked, not even turning but her voice was dark, cold, it made John tense, it was the same voice she had held when the two served their first tour together,
"Belleview High." Finally she turned around with wide eyes,
"No. No it can't be. No!" The 26 year old was filled with a frenzy of worry and anger as she stared towards the screen and then back to her 'brothers' and her 'sister' before speaking,
"That's my old school! Andy and Lauren should be attending now, that's where they would've gone!" John came over to her, placing one of his hands on either of her shoulders,
"Just because it's their school doesn't mean it was them." Adaline shook her head, John's soft voice not calming her,
"Don't give me that! You and I both know that they have a higher chance of being mutants because I was born one." John wrapped his arms around his friend as her knees buckled at the thought of her younger siblings being in danger. She had fallen out with her parents yes, but never with Andy or Lauren, they were 5 and 7 when she had left, they wouldn't really remember her now. Ada's pale blue hair framed her face as her john looked into the eyes the colour of orange autumn leaves.
"Do we help them?" Marcos asked,
"No." Adaline spoke in a shaky voice as she shook her head,
"We help them if they contact us. I'm not making them live in fear if they don't have to." The other three all nodded and they all left the room heading for their beds.

The night passed painfully slow for some of the permanent residents at the HQ, one of their own was missing and they didn't know how to help them. Natalie spent the following morning answering Sage's questions but by 3 pm she found Marcos in the vault as he tried to find a way to break Lorna out of jail, the four girls had been playing random games since about lunch time so every now and then a burst of colour would go sprinting past before disappearing. Natalie knocked on the vault door before entering,
"Is this your dog?" Natalie asked, Marcos cast his eyes to where Zingo was lying on the couch,
"She - uh - she's everyone's dog really." Natalie walked over to the couch and began fussing the dog,
"Look, I just wanted to say thank you... for, y'know, savin' me. Even though I threw a coffee pot at your head," Marcos let out a breath,
"And a mug," Natalie smirked,
"And a mug," she repeated, Marcos shook his head slightly,
"Don't worry about it," he said going back to cutting a cement block with his lasers. Natalie sat on the couch looking around,
"So this group? You guys run it?" She asked looking back at Marcos,
"The networks nation wide, founded after the anti-mutant laws first..." His voice faded as a mass of deep blues and greens ran into the room and threw herself over the couch, landing on the concrete floor with a thud before muttering something incoherent,
"Aurora?" Marcos asked causing the girl to peer at him showing as little of herself as possible,
"yeah..." she drew out, looking directly at Marcos then to the doorway and then back at Marcos again,
"What are you doing?" He asked, feeling like he should be slightly concerned,
"Hidin'!" Aurora exclaimed causing Marcos to nod sarcastically,
"Yeah, I can see that. I meant, why?" the four year old rolled her eyes in a way that Marcos knew would've made Lorna proud,
"Cos Evie gotta come find us so we have to hide" the child exaggerated with a sigh, Marcos shook his head as his daughter slowly disappeared behind the couch,
"Why did I even ask," Marcos muttered just as a bundle of neon bounded into the room, took one look at Marcos and left just as fast as she had entered.

"There are kids here?!" Natalie asked slightly shocked,
"Yeah, there are four permanent residence who are kids, mine and Lorna's daughter, Aurora. John and Clarice's two, Eva and Rosie. And then there's Imogen who's Adaline's." Natalie nodded before returning to her earlier conversation which carried on for about 2 minutes before Natalie saw a girl with black hair with subtle streaks of blue in it come to the doorway, she was the most ordinary looking of the girls until Natalie saw her eyes, they were electric green, the girl folded her arms over her chest covering the dinosaur tee she was wearing and look Marcos up and down before entering the room. Her electric eyes scanned the area before she held her left hand out and flicked her wrist, using her powers to lift the couch like it was a sheet of paper, Aurora clung on as long as she could but Eva began shaking it making her friend fall,
"Got you!" Eva, the younger of the two, yelled,
"Yeah but you cheated! Tell her daddy!" Marcos shook his head,
"She used what she could." Eva giggled at her uncle while Aurora stuck her tongue out at him before the two took hands and ran off, a faint green glow following them.
"Eva manipulates atoms, Aurora can control nature. The two can combine their powers and control natural disasters. The other two can combine and they get elemental weapons, Imogen controls biological objects and Rosie can manipulate elements." Marcos explained to the woman who was watching the forest green light dissipate,
"Well then they all combine and they get absolute control, they can control anything and everything. That one terrifies them so they don't really use it." Marcos added, Natalie looked over to him with a slightly questioning glace making him shrug his shoulders.

Just then, Marcos' phone rang, flipping it open he saw a number he didn't recognise,
"Hello," Marcos said calmly, getting up from where he was sat,
"Is this Marcos Diaz?" The voice on the end of the line asked,
"Uh-huh. Who's this? How'd you get this number?" Marcos asked,
"My name is Reed Strucker" Marcos looked over to where Ada was stood with her back to him, watching the children while chatting with Clarice,
"My family needs help getting across the border. You and the people you work with, you do that right?" Strucker asked, Marcos didn't take his eyes from Ada but answered the man,
"Maybe." Marcos stated, giving nothing away,
"Did you hear about the mutant incident? At the high school? Those were my children." Marcos took his eyes from Ada,
"I'm sorry I can't-" before Marcos could finish, Strucker interrupted him,
"I was a prosecutor for the city. I was responsible for building a case against you and your associates for the districts attorney's office." Marcos rolled his eyes, this man really wasn't giving him a reason to help him out.
"And you're calling me for help? Why should I lift a finger for you?" Marcos hissed,
"Because I can help you. Your, uh, your associate, Lorna Dane, goes by Polaris?" Marcos stopped walking suddenly,
"What do you know about Lorna?" He asked with urgency,
"You want to help her, you can talk to me. You know about her medical condition?" The man said calmly,
"What are you talking about? What medical condition?" Marcos asked, panic evident in his voice,
"You gonna help my family?" The man asked, son of a bitch Marcos thought,
"What are you talking about?" He hissed again,
"I want a meeting!" The man on the other side snapped,
"Yes. Fine. I'll meet you, just tell me!" Marcos' voice was low but was venomous,
"She's pregnant." The man stated simply. Marcos gave him the location of Fade's bar knowing that it would be the best place to meet if the man were to bring cops.

Marcos left the underground quickly and was gone about an hour when Natalie came up the stairs to find John or Clarice or someone who would know what to do. As she approached the top of the stairs she saw John and Clarice going over a map and a list with another member of the HQ. Clarice was sat on John's lap with his arm wrapped around her,
"Go see what you can do." Clarice said, handing the man the list before turning to Natalie,
"What's up?" Clarice asked in a cheerful tone,
"I need to talk to you. It's about Marcos…" John sighed while Clarice chuckled,
"Look, Marcos… He's an emotional guy. So whatever he said, just don't take it personally." John said calmly while his hand drew circles in Clarice's side,
"No. it's not about that. Its – he got a phone call from some guy, something about helping a family. He ran off about an hour ago," Clarice stood up at this, John's hand remained on the small of her back,
"Alone." Natalie stated,
"What?" Clarice asked shocked,
"Why didn't you tell us?" John pushed, standing up himself and walking from behind the desk,
"Because he told me not to, and he didn't want to get anyone else involved, because it was dangerous. But then I thought about how I owe his girlfriend, and she'd be pissed if he died." Clarice sighed,
"C'mon," Natalie looked at her,
"What? We don't even know where he is!" She called after the pair,
"I found you. Trust me. I can find him," John said calmly before heading down the stairs, on the way they saw Ada,
"Hey Addie, can you be a star and put all the girls to bed tonight?" John asked,
"I was going to anyway." She said, kissing his cheek. John shook his head at her antics before he caught up with the two women.

Ada reached the door to the girls room, she burst it open,
"The floor is lava, mo-om" Imogen yelled to her mother,
"Well I'm dead then." She said before smirking and hopping onto one of the beanbags,
"C'mon bed time." The four girls groaned in chorus which made Ada chuckle,
"Pyjamas at least," The girls all looked at Ada with suspicion,
"Where's momma and daddy?" Eva asked, as she did so, the girls stopped manipulating the air or making the beds float (A/N Rosie manipulate the elements while Eva is the one making the beds float) and they all flopped down onto the beds,
"They've just had to go out to get Rory's dad out of trouble," this caused all the girls to laugh,
"Right! Pyjamas and then you can play for 5 more minutes. No more!" All the girls cheered and raced to get their pyjamas on so they could keep playing. The girls all grabbed their pyjamas as quick as they could, Eva changed into her dinosaur ones which said 'Don't wake sleepy Dino', Rosie's were Beauty and the Beast ones, Aurora's were Harry Potter ones that said 'Don't let the Muggles get you down', and lastly Imogen pulled on her ones which were covered in ice creams with faces. All the girls grabbed their stuffed toys, Imogen's was a rhino, Rosie's was a penguin, Aurora's was a frog and Eva's was shockingly a dinosaur. The girls were quick back to playing but didn't get long because true to her word, Ada came back in five minutes later and helped get the girls into bed. She began reading a story when suddenly there was yelling and a load of commotion downstairs. Ada looked at all of the girl's scared faces,
"Stay here. I'll be back. If I'm not, come and find me." The girls nodded but couldn't sleep. They each clutched a soft toy while they sat in pure silence. After almost five minutes, the girls all decided that they wanted to see what was going on, they headed out of the door and saw Clarice lying unconscious on the bench and Ada was yelling at a woman and two teenagers.

Right second chapter is already started so hopefully should be updated by the end of this week but my exams are starting so I will have very little time to write this week and next week. Don't lose hope xD