Title: Growing Pains
Chapter 1 – Telling the Unthinkable

Summary: Working full time and now looking after Heather's boys would be a challenge for Casey. Despite his past tension with Heather, Severide decides to help his friend but what other danger is lurking from the arsonist? Will the makeshift family survive? Or will anyone else suffer a fiery end? Based on some parts of eppy 2.01 'Problem House' and 2.02 'Prove It', Contains some spoilers

Disclaimer: Chicago Fire and its characters are the property of Dick Wolfe, NBC and….well sadly not me

A/N: Okay so right from the time they said Casey was going to look after someone's kids…me and my few trusted cohorts were already discussing this like crazy and then suspicions confirmed it was Heather's kids. Wow didn't guess the cause though (I had something else in mind). So this is a piece based on the idea…and I'm going to give it my own AiP/Alice spin and hope you all like it. It will be multi-chapter and #teamsevasey of course (ha how cool is it that Jesse even said that on his today show interview!) And as always with this there is NO SLASH! Sorry I don't write that despite their amazing on-screen and off-screen chemistry. But two men can be very close friends and have a very strong friendship and help each other in crisis time and that's what this is going for. So….please enjoy!

NOTE: "Words in italics and double quotes taken directly from the eppies."

He had intended to spend his time off, relaxing by the lake, fishing and just trying to get his head cleared up. But when he got the call from Heather Darden, saying she was doing some home renovations and asking if he wouldn't mind helping her, he was quick to say okay and switch his attention from the country back to the city.

"I really do appreciate this Matt," Heather tells Casey as they both sit on her back deck, watching her two boys, Benjamin 'Ben' and Griffin tumbling around in the backyard.

"No problem," Casey looks at her with a small smile. "Was happy to help. Plus it was good to see the boys some time other than at night or on just a weekend."

"They love having you here. Ben especially."

"Griffin's missing his dad," Casey notes as both look up and yell 'hi uncle Matt' and then get back to their game.

"More and more every year," Heather replies with a heavy sigh. "It's just not the same anymore for them. Griffin still won't go to the firehouse. Stacy's husband got us all tickets to the game last weekend and we went…they saw other boys with their dads and it was tough. Ben bounced back easier than Griffin did but I could tell by them both being so quiet on the way home it just wasn't the same."

"You know I don't mind taking them some time," Casey reminds her warmly. "I'm not their father but…"

"But they do adore you," Heather states rather matter-of-factly as she watches her boys with a contented smile. "Next week…"

"Yeah next week," Casey agrees softly as his face develops a small frown. "The year has gone by so fast."

"Too fast. The boys are growing up so fast and already starting to get so busy. One wants to join the baseball team the other likes soccer better. Ben comes to me and says he might like to take karate while Griffin wants to join the computer club. Ben is more open with his feelings while Griffin just wants to clam up take it all in stride but not say much. Ben is happy go lucky and Griffin's more moody. Not having Andy here to temper all that at times…sometimes stretches me a bit thin."

"I don't mind talking to the boys at times if you need me to," Casey suggests in a low tone. "Just say the word."

"What would I do without you Matt," Heather smiles as her head rests on his shoulder; his arm automatically wrapping around her and pulling her close. When Heather had first made a play for him a few months before Hallie returned he knew inside his heart that he wasn't quite ready; even now…he tells himself that while he's attracted to Heather and adores both her boys, to take things slow. It had only been just over a month since he lost Hallie in such a tragic way and wasn't sure inside what he wanted. He knows he wants a family…a wife to stay home and look after his family, a few children at least but when…that was the big question. He had made it very clear to Heather that he just wanted it to be really slow and she agreed; she hadn't pushed him further and that was a comfort. However, Heather was still tense whenever the subject of letting the boys spend time or see Kelly Severide on a regular basis came up and that was still a bit disconcerting to him. He and Kelly had finally worked past their tension with Andy's death and were well on their way to cementing a strong and loyal friendship.

But one of the things that didn't sit quite right with Casey was the fact that whenever he'd bring up the subject of him and Kelly taking the boys out, Heather would make up an excuse. He did call her on it one time though…

'Heather what do you have against Kelly? I thought you two had for the most part worked things out?'

'It's just that…Matt when I look at Kelly I remember the times he and Andy shared and Andy always told me…if it wasn't for Kelly Severide I'd never be doing what I love. It's because of him and on he went.'

'But you do know that if Andy had wanted to do something else…no matter what it was that he would have done it right? Kelly's love for being a firefighter might have helped Andy decision but in the end…it was Andy's choice.'

'And the finding that…'

'He didn't do it on purpose.'

'I know Matt and I'm happy that you two have worked past everything. I don't hate him…I've tried to work past that but…but it's hard to see him around the boys and not feel that resentment. And I'm afraid if he's around them and I see…they'll feel that and it's not fair to any of them. Especially Ben, he just adores Kelly. I'm sorry Matt.'

'Just doesn't seem fair for the boys. They asked about him again last night. Taking them for an outing would be good for them and him. Kelly misses them too. He misses being a part of their life. He was Andy's friend before me and I…'

'Feel like you are taking that away from him?'

'Sometimes.'

'Okay I'll try.'

But, as much as Heather had promised she'd try…drop them by the firehouse from time to time…the situation never presented itself and so Casey was forced to tell Severide briefly about his outings with the Darden boys; holding back much enthusiasm as he knows Kelly and Andy were friends before he came along and it just didn't seem fair to him that he was the one to be Heather's shoulder to cry on and the male figure in her boys lives, while Severide is out in the cold watching from the sidelines.

"Want to stay for dinner?"

"Love to," Casey replies with a firm smile.

"Boys, want Uncle Matt to stay for dinner?"

"YES!" Both answer with an enthusiastic smile.

"I'll fire up the barbeque," Casey chuckles as both adults stand up. He slowly walks down the stairs and is instantly tackled by both exuberant children; Heather watching with a contented smile as the three of them wrestle around on the ground a bit. Her affection for Matt Casey was growing by the day and she would only have herself to blame if something was ever done to destroy their blossoming relationship.

XXXXXXXX

The start to Casey's first week back was met with bittersweet emotions. Kelly's car was torched – basically a write-off. Boden told them their house was under review – no side trips or unnecessary spending. They'd be sharing a locker – to make room for extra equipment from a closed house. And the anniversary of Andy's death.

"Can't believe it's been a year," Heather tells Casey as they stand in her kitchen a few days before Thursday, the anniversary of her late husband's death. She had told him that both boys were starting to notice her moods change a bit the closer the day drew near and so all of them were a bit more on tension that normal. She hears them and then calls them for breakfast. But as soon as the older boy looks at Casey, he stiffens and then displays an angry expression.

"I'm not hungry."

"Griffin Darden," Heather lightly scolds, looking at him in wonder before she looks at Casey and it finally dawns.

"I'm not hungry!" Griffin snaps as he turns and rushes back toward the front door.

"It's the shirt…anything with the fire department logo on it."

"Damn I'm sorry Heather," Casey softly curses as he gives his head a shake. Heather had told him right from the start that griffin was more sensitive about his father's passing; Ben being more like his father and just seeming to shrug it off a bit easier. He had made a careful note about not talking too much about things going on at the firehouse so as to spare Andy's oldest son that emotional anguish. But today he had been in a rush and it slipped.

"He'll get past it," Heather tries to assure him as he looks at her with a glum expression and then at Ben who merely shrugs as his brother's recent actions. In a way, Casey could relate more to Griffin than maybe he voice openly. Things about his father's death or even Hallie's…would haunt him in ways he might not have realized or imagined. He would pull away or push people away and only a handful, mostly Kelly, would have the strength to withstand the emotional onslaught and help pull him back to reality.

"I'll talk to him," Casey tells Heather in a kind tone as he leaves her and Ben in the kitchen and goes in search of Griffin; finally finding him sitting quietly on the front steps. He plunks himself down and looks straight ahead for a few seconds in silence; happy that the boy hadn't left or pulled away when he arrived.

"Griffin, I'm sorry," Casey starts in a soft tone.

"Whatever," Griffin mumbles in haste; Casey pressing on undeterred.

"Your mom had told me about wearing fire department stuff but I was in a rush and didn't think. I never wanted to upset you on purpose, especially this week."

"It's no big deal."

"Yeah I said that too after my father died."

"How old were you?"

"A few years older than you. At least you still have your mom. Mine went to jail."

"What? For what?"

"Killing my dad," Casey answers matter-of-factly. He had approached Boden after Andy's death, seeking specific advice on how to talk to young ones about death and matters surrounding that. Boden had reminded him that Andy's boys weren't babies and were at the age where they could process the facts. You didn't have to elaborate on the facts but they'd catch a lie if offered and then trust would be broken. 'Sometimes it hurts…but the pain will pass,' Boden had reminded him, 'but if you lie…they'll always remember and it won't pass.'

"That sucks," Griffin states with a frown as he looks away; Casey offering the childish answer a small smirk and nod.

"It sure did and even now…over fifteen years later there are still certain people who will say or do things…or even perhaps wear something that will make me angry at them. But you know they don't do it on purpose," Casey tries to explain; leaving out the part that there are those, however, that do do it on purpose, just to make him angry. That was moot right now as he knows his motive wasn't to emotionally injure the boy on purpose. "I'd never to anything to hurt you on purpose Griffin so I'm sorry. Forgive me?"

"Yeah," Griffin shrugs lightly; his face, however, still stoic.

"Okay how about I drive you guys to school."

"Okay."

Casey leads Griffin back inside, earning a very heartfelt 'thank you' in private from Heather; the four of them sitting down to breakfast before Casey drives them to school and then heads to work. He enters the quiet firehouse and heads toward the locker room, offering a small grumble about the absurd fact that they were on the shortlist of active firehouse's to cut. 33, to him actually made sense as it wasn't too far away and they could easily cover their territory. But the next house wasn't close and so forcing them to close and having the next one cover could actually cost lives. Whose brilliant idea was this anyway's…he inwardly huffs as he reaches his shared locker.

He opens his shared locker with Hermann and then glances at the picture him, Andy and Kelly taken a few months before Andy's death and feel his fingers reaching for it. His mind senses movement behind him and his eyes lift to see Severide's reflection in the mirror.

"Almost one year," Casey mentions quietly as he turns to face Severide with a frown.

"How's Heather?"

"She's…coping," Casey turns to his friend with a heavy sigh. "Griffin's feeling it more than Ben, but then I think Ben has more of Andy's careful attitude."

"Yeah," Severide replies a bit stiffly.

"Kelly…"

"Hey man whatever…Heather still has hard feelings that's her issue. I'd just like to see the boys sometime you know?"

"How about we take them out this weekend? Just the four of us."

"Matt…"

"She's okay with it. She even told me she doesn't want her personal feelings toward…well how she feels about Andy's death to be put on the boy's, she wants them to make up their own minds. Come on…this weekend. We'll take them to the park or something…just hang."

"Hang."

"You driving?"

"I'll borrow Hermann's mini-van," Casey smiles. "He's always happy to drive the truck whenever he can."

"He'll be able to survive without his school bus?" Severide retorts; Casey happy his friends tone was lighter, signaling he wasn't holding onto agitation toward him. He too had agreed with Heather to let the animosity between her and Kelly be worked out between them in private; he was both their friend's and wanted it to remain that way.

"Ah my team's a hearty lot. Besides…I can just take his keys," Casey jingles Hermann's van keys and then shoves them back in his jacket pocket; Severide giving him a small uneasy smile before he opens his own locker. Casey watches Severide take his leave and then turns back to the picture of the three of them and frowns. "I'm trying here…" he whispers directly to Andy as he closes the locker door and then heads into the main eating area to get his day started.

The day passes by with a regular rescue; all the tension building up for the following day. Thursday morning, Casey awakens with a tight stomach and mind filled with agitation. As much as he doesn't want to, his mind forces him to recall the events of the morning of Andy Darden's death, a year ago do the day. He recalls the three of them joking around before shift, laughing with Severide on the ride to the call and then how things turned absolutely horrific on a seemingly routine call.

'Darden!' Casey recalls shouting, seconds before he hears the door slam and his close friend is caught in a flesh hungry backdraft. The fireball consumes Darden, Casey shouting at him before he is forced to duck, the superheated fireball swooshing overhead before he's able to look back up and resume his climb, racing up the last few rungs but knowing inside it was only to confirm the inevitable – Andy Darden was already dead.

"Damn it," Casey whispers softly as he pushes himself out of bed; not wanting to dwell on the events that followed as he knows it led to him and Severide's tension filled showdowns until he nearly lost his life and then both were forced to face the facts – life's too short and precious to spend their days in hatred and resentment. They made up and moved on and were much stronger for it.

So he decides to focus his mind on something else – the weekend out with Kelly and Andy's boys. He sends a quick text to Heather, telling her he's thinking of her and hope she's able to have fun with her friends.

"Man you know we'll get into trouble for this."

"Cruz it's on the way back from the scene and I swear it'll only take a few minutes," Casey tries to justify his side-trip to see Heather and her friends at a favorite restaurant. He recalls Boden's strict warning about no side trips and to watch all fuel costs; a small voice reminding him that he was their team leader and it was up to him to set the example in carrying out the verbal order Boden had given a few days earlier. What will your team think? But he tells himself it was for Andy's widow on the day of the anniversary of his death and the Chief would understand. Besides…I won't do it again…for another year at least, he inwardly justifies.

"Trust me Cruz nothing will go wrong," Casey utters fatefully before he heartily slaps his driver on the shoulder and then hops out of the large rig and hurries inside. He spies Heather from a distance and heads toward her, wanting to put in a small show of support given the fact that he couldn't actually sit and have a round with her as he was right in the middle of a set of shifts.

"Thanks for taking this one out."

"Matt's still on shift, otherwise he'd join us for a shot," Heather explains with an almost giddy smile.

"This rounds on me. Be safe," Casey tells him as he puts down a few bucks on the table and then turns to leave.

"Thanks. I'll call you later," Heather whispers as Casey plants a small kiss on her cheek and then pulls back; offering the other ladies a friendly smile before he hurries back out.

"See told you…nothing to it. We'll just say we stopped for a cat in a tree," Casey slaps Cruz on the shoulder as the big rig starts to life. But it's only a few seconds later that they get the call and it's back to serious business. On the ride there, Casey's mind thinks about Heather and her boys and how they should be spending the night together as a small family. But at the same time, he knows, it's not his place to judge her parenting as he wasn't her husband or their step-father and to just hope that she has a good time and they are all reunited safely. They reach the burning apartment, and his thoughts about the Darden clan are put on hold until after the fire is put out.

XXXXXXXX

"You okay?" Severide asks in concern as they get back to the firehouse after the tense rescue.

"Yeah fine. A bit sore but I'm okay. What about you?" Casey asks Severide directly. "I heard what Clarke said about the same diesel accelerant. Same arsonist."

"If this bastard wants to have a showdown just wish he'd come at me instead of all this cloak and dagger crap."

"Kelly…"

"I'm fine…just angry. People nearly died and you…" his voice trails off as he exhales heavily. "Today of all days you know?"

"Yeah I know. A few more hours in shift; but after how about we go to the nearest pub and drink a midnight toast to Andy and come back here."

"You're on."

Casey watches Severide head for his office to finish his paperwork and then heads into the eating area, arriving just in time to call out Pouch poop duty and then help to diffuse a tense situation between Hermann, Otis and Cruz. But it's Mouch to the rescue with his announcement that he'd be running for union president; something that makes all of them smile.

That jubilant celebration, however, is short lived by another call to "truck 81…ambulance 61…single car accident…" and its all hands on deck. His mind is focused on Severide and the arsonist and how Kelly must be feeling after learning the news about the evidence, especially on the anniversary of his childhood friend's death.

But those thoughts quickly change as he hops out of his rig and spies the two cars involve; overhearing the CPD talking about a "DUI" that might have caused a fatality. But as he nears the smashed car his panic starts to build. He spies the wounded woman on the stretcher as she is pushed by by Dawson and Shay, overhearing she's losing a lot of blood and might not make it; his panic building further as he recognizes the woman as one who was with Heather earlier. Oh god no…no this can't be…she would never….oh god no…Heather! His mind races as he looks at the smashed up car, his stomach sick as it correctly identifies who it belongs to. But it's not until he hears her frantic voice and turns to see her being put into handcuffs that his worst nightmare is justified as reality.

"Heather!"

"Oh thank god Matt! Matt the boys…you have to get the boys!"

"I'll take care of it!"

"They're at the babysitters!"

"I'll get them!"

The car door slams shut and the marked police car drives away with its sirens blazing, his mouth agape and his mind literally asking…what the hell just happened? He stands in the middle of the intersection and doesn't move until he feels a hand on his shoulder and turns to see Hermann looking at him in concern.

"It was…Heather," Casey states as if not even believing his own words. "Hermann she…this can't be happening."

"Come on…we're done here. Let the CPD handle the rest. Let's get back to the house."

"Hermann she…Heather would never do that," Casey insists as he looks at his fellow truck 81 team member with a blank stare. "She knows better. She has the boys and tonight…damn Hermann it…she knows better…this…this isn't really happening…" Casey's voice dies out as he turns and numbly walks back to the truck in silence; the rest of the team watching with silent but dumbfounded expressions. Even the ride back to the firehouse is spent in contemplative silence.

As soon as truck 81 stops, Casey hops out and sees Severide look up from his game of cards with his team and smiles. Casey tries to smile back but is unable; he can merely stand there in silent shock, prompting Severide to get up from the table and come over.

"What's going on?" Severide asks in wonder as Hermann offers him a somewhat sheepish expression. "Cruz?"

"I'll let Casey tell you."

"Tell me what…Matt? What's going on?"

"We um…" Casey pauses, suddenly feeling all eyes on him.

"The single car accident right? What happened?"

There was no easy way to say it and no point in sugar-coating the truth. "It was…a DUI. Kelly…Heather was the driver."

"What?" Severide asks in shock. "Where Ben and Griffin with her?" His voice raising as Boden comes to join them.

"What's going on here?" Boden instantly wonders.

"Heather was the call we just attended to."

"What?" Boden asks in shock.

"Matt who was with her? Were the boys?" Severide presses again.

"No…her friends had taken her out earlier and the boys were with Eve. I recognized one when I got there and…" Casey pauses as he looks up at Boden. "It was a pretty bad accident. Her friend Jen…damn it Kelly she might not make it."

"Oh god," Boden lightly curses under his breath. "Where are the boys now?"

"They're with the babysitter. Chief, permission to go and get them…at least let someone they know pick them up before they start to panic or Eve makes the wrong phone calls."

"Go," Boden directly as Casey wastes no time in pushing past his team and heading for the lockers, Severide in tow.

"Kelly I don't know anything else," Casey tosses back. "I got there…saw the smashed up cars…saw her friend being pulled and then…damn they were taking her away in handcuffs. She seemed fine and…I mean damn today of all days…no wait…it's wrong no matter what but…"

"Today of all days. The day Andy died," Severide repeats softly as he helps Casey pull off his coat and then boots. "Want some company?"

"Nah I got this. I'll just pick them up take them back to my place for the night. Heather will probably get a fine and…and probably probation and be back home tomorrow or the next day," Casey tries to explain; hoping the words he's uttering come true.

"Call me if you hear anything else."

"I will."

With that Casey grabs his coat, slams his locker shut and then darts out the back exit doors and into the night. On the drive over to the babysitters, his mind races as to what he'll actually tell her two boys. Your mother was out for a few drinks and then…decided to get behind the wheel. Damn it Heather, Casey's thoughts pause as he slams the dash with his fist, how the hell could you drive drunk! You know better… As much as he wants to tell himself this is all a bad dream, he knows, that especially today, she'd never put her children through anything like that. This was as real a nightmare as it gets and a nightmare he fears is only the beginning. Best case scenario – her friend lives and she gets a fine and possible license suspension. Worst cast scenario? ….he didn't want to go there because that could mean Heather possibly going to jail and possibly losing her children. This can't be happening.

Casey knocks on the door to the babysitter, offering an uneasy smile when the door opens and he greets Eve; his mind conflicted as to what to say. In the end…it was a lie; his mind convincing him it was for the sake of the boys and it would be okay; Heather would understand and agree.

"Where's mom?" Griffin asks with a small yawn.

"She's on a little trip and will be back soon. You'll stay with me overnight," Casey explains as he carries Ben in his arms to his truck and guides Griffin with his other arm. "It'll be okay," he tries to assure them.

"Where'd mom go?" Griffin asks in wonder as he looks out the window of Casey's truck.

"To a….uh some girl thing. She'll tell you about it later," Casey answers in haste. The rest of the trip home is spent in silence with Casey hoping and praying that his thoughts about Heather getting away with just probation would come true and the things would be back to…normal? Things won't be normal after this, Casey's mind laments in misery. But he puts confronting Heather on hold to focus on the boys for the rest of the night.

"Okay…here we are. Change into your pajama's and let's get to bed okay? You two can share the larger one and I'll take the single for tonight."

"We're gonna go back home tomorrow right?" Griffin asks with a small huff.

"Should be tomorrow."

A few hours after Casey puts the boys to bed he gets the call he had been dreading.

"Heather's friend Jen died…she's being charged with manslaughter," Antonio tells him.

Casey utters a deft 'thanks' and then quickly texts the one person who should hear it from him. Half hour later, he hears a soft knock at the door and hurries to open it. "Kelly."

"Hey man I know it's late but I got your text. Damn…manslaughter? Really?" Severide asks in shock as he enters Casey's quiet home.

"Jen died and she willingly got behind the wheel. Damn it Kelly she should have known better," Matt hisses in a soft whisper as he grits his teeth. "I spoke briefly with her and she thought taking the plea deal for fifteen months was the lesser of two evils. I mean she's right if it was directly up against the five to ten years that she could have gotten. But that…that would have killed the boys and we all know it. As it is…fifteen months," Casey's voice fades as he shoves his hands in his pockets and leans against the wall, looking at Severide with a heavy frown. "I thought she could have tried for less…first offense, single mother of two small boys…never in trouble before but she…she took the deal."

"You tell the boys yet?"

"No they think she's on a small overnight trip," Casey shakes his head as he looks away and then back at his friend.

"What?"

"When I talked to Heather she…she asked me to look after the boys while she's in jail."

"Really?" Severide looks at Casey with a tight frown as his mind races back in time.

'Kelly…you're the brother I never had and if something…'

'Andy…buddy nothing's going to…'

'Kelly, just do it for me okay? Something ever happens to me I want you to look after Heather and the boys. Especially the boys. For me. Please?'

'Can I say no?'

Severide remembers tossing back a small joke but then gave Andy his word. Now hearing that Heather had asked Casey, stabs him to his heart and he can only look back at his friend with an absent stare and utter…"you?"

"Look, I'd want you t…." is all Casey manages before Severide pulls away from the wall shaking his head. Good thing I didn't tell him that she had talked to Andy while he was still alive and they both agreed to put me in their will as the boy's guardian. "Kelly…"

"You," Severide states with some disdain. "You weren't even Andy's friend as long as I was. I guess sleeping with his widow gives you that right now and not me," Severide growls before he heads for the front door, pulls it open, slams it shut and leaves Casey standing in his front entranceway – speechless.

A/N: Well? How'd you like the first part? I'm kinda torn b/c I do like Heather (or did when I thought she was at first dealt a raw hand) but its hard for me to work past someone who chooses to drive drunk *sigh*. There some other parts from this second eppy that I missed but will come up in the next chappy!