Author's Notes: So this idea came to me while working on "Save You." It didn't really fit into what I had planned for that story so it has begun to take on a life of it's own. I won't be updating this as frequently as "Save You" but I figured I would put this out there and see the Lindseride community thinks that this is worth continuing.

For timing, this takes place sometime in the future when Lindsay and Halstead are back together. I'm going to choose to ignore the proposed pairing of Serveride and April Saxton for the purposes of this story. The story will eventually have some mature scenes.

Chapter One

"We have decided not to pursue this case," Captain Lynette Cunningham stated and closed the folder that sat on her desk. "There is not enough evidence for us to focus CFD resources at this time."

Kelly Severide was astonished at the decision by the Office of Fire Investigation of the Chicago Fire Department. He stood up, slammed open the door to her office and stormed from the room, leaving Chief Boden to thank Captain Cunningham for her time and follow his hot headed squad lieutenant as they exited the central office for the fire department.

"Chief, three fires – three fucking fires in our jurisdiction in the homes of couples that are supporting multiple foster kids. And not lowlifes either! Good, salt of the Earth people who have been making a difference and they don't see a pattern?"

They went out into the tail end of another bitter Chicago winter and got into the chief's truck in order to head back to Firehouse 51.

"Severide, we can't go against the wishes of OFI. For the time being, we have to do our best to take care of anything else that seems related to these cases."

"That was a politically correct answer if I've ever heard one," Kelly grumbled.

"I don't like this any more than you do Kelly," Boden said. "This creature threatens the good that people do in the world. I don't take kindly to that and neither do you. I do have faith that OFI will act when there is enough evidence to warrant a proper investigation."

Boden pulled the car into the house and the two exited the vehicle. Severide felt defeated as they went into the kitchen area and all the eyes of the men and women of 51 looked at the two of them for information. No one liked what was going on in the neighborhood that they served. Severide took a seat at the table and let Boden deliver what he was sure was going to be an unpopular message.

"OFI has decided to not investigate the three fires that have occurred over the last three weeks in our area. There is not enough evidence for them to allocate resources at this time. As I told Lieutenant Severide on our return trip back to this house, we will do our best to combat anything related that happens and hope that OFI chooses to investigate at a later date."

Shoulders slumped at the chief's announcement and Kelly focused on reading the day's paper. But in between reading about the upcoming opening day for the White Sox and the Cubs as well as trades that the Bears were making, his mind unwillingly went back to each of the fires.

All three had been alarms in the early morning hours when members of 51 had been trying to grab some sleep in between calls. Roused from sleep, everyone had pulled on their turn out gear and traveled to the addresses called out of the intercom. The first fire they had been able to enter the building and had attempted to rescue the inhabitants, which had been to no avail. The one child that they had pulled out of the house with a pulse had expired once she got to the emergency room.

The next fires were so overcome by flames and thick, black smoke that Boden hadn't let them enter the homes out of concern for flashover. Ultimately, the chief had been right thanks to his many years of experience. The last two houses had burst into giant fireballs right in front of their eyes. Everything and everyone inside had been incinerated. They had had to call in backup to put out the flames.

The thought of those families twisted his gut. They had gone to sleep believing that they had more time only to be overcome by the thing that firefighters were supposed to be able to defeat. Severide made the decision as everyone rolled back into the house after another call that night. He knew that in order to change the minds of the brass at OFI, he would need to find his own evidence just as he and Dawson had done with the warehouse fire that had killed Shay.

"Rice, cover me for an hour," Severide told his friend and put his radio on so that he could run an errand.

It took him about ten minutes to cross town in his blue Mustang even though there was limited traffic out at that hour of night. He went to apartment 310 and knocked, waiting for the occupant to open up. Severide honestly wasn't expecting the Erin Lindsay that came to the door. Her hair was mussed, her eyes bright, lips were swollen and cheeks flushed. He had certainly interrupted something.

It had been awhile since he had seen her but the physical attraction that had once been there certainly still existed. He remembered when he made her look like that and immediately had to push that thought from his mind. They were not together any more thanks to his doing.

"Kelly, what are you doing here?" Erin asked, becoming serious.

"I know it's late but I need your help."

Detective Jay Halstead appeared behind her and sized Kelly up. Gabby had told him awhile back that the two were dating but he hadn't realized that it was still a thing. He was sure that the detective didn't appreciate his presence at Erin's door at 11 pm, no matter the reason.

"I'm going to order the Chinese, okay babe?" He kissed her on the head and disappeared into the apartment.

The flagrant act of making sure that Kelly knew his place severely pissed him off.

"Should I step back?" Kelly asked Erin, "Give him some room to pee on you and mark his territory?"

He knew it was a low blow when Erin's eyes narrowed in anger.

"Don't be an asshole Kelly. You came here needing my help remember?"

He rubbed the back of neck. He was aggravated at the situation that he was facing at 51 and even more aggravated at finding Erin in an inconvenient situation. Wasn't she the one that told him that he never needed to call?

"Listen it was a bad idea to come here this late. Can I meet you tomorrow at the district? I'm off so it's whenever you have time."

Erin cast a look over her shoulder into her apartment and Kelly figured she was debating what the man ordering Chinese food would think.

"Noon? You can buy me lunch to make up for the comment."

"Done. That going to be okay with him?"

Erin shrugged her shoulder. "He'll have to get over it."

Kelly knew that Erin was too independent to let a man control her every move, even if that man was also her partner on the force.

"Okay, noon tomorrow."

She nodded and shut the apartment door. Walking away from her door, Kelly hated the feeling that settled in his gut. It was his fault that she was now someone else's.

Kelly met her at the district and they had walked a few blocks to grab lunch. They settled on a burger joint since it wouldn't take long to get food and get her back to the office.

"So we've exchanged niceties - weather, how we've been, plans for the weekend. Now, to the reason that you were at my door last night, insulting me and asking for help."

He knew the tail end of her sentence was not meant to be a barb but instead teasing him for his offhanded comment the night before. Kelly gave her a smile before he laid the somber information on the only female detective on the Intelligence team.

"Three instances of what we believe to be arson in the homes of foster families. Fourteen kids have died and six adults."

Kelly saw the color drain from her face at the news. She had given him some insight into her past while they had been together. Although she hadn't been a foster kid by Illinois state standards, Hank Voight had turned her life around when he had taken her into his home. Her brother, Teddy, had been in the system and had suffered significantly. He knew how much Erin would care about this particular case.

"Confirmed by OFI?" she questioned when she had processed what he had told her so far.

"That's the thing. They have refrained from designating resources to investigate. They feel there is a lack of evidence."

She rolled her eyes at the decision from the arson team of the Chicago Fire Department and it wasn't for the seriousness of the situation, he would have smiled at her reaction.

"So you want Intelligence to look into it?"

"I want you to look into it, quietly. I don't want it getting back to OFI that I went around their decision."

Erin didn't even have to question why he was asking her for help. She already knew.

"Let's go speak to Hank after we're done here."

Erin breezed past Jay with Kelly in tow, headed straight for Hank's office. She knew that he would have questions but right now, she was more concerned with getting Hank's blessing on her helping out in this investigation. Erin knocked on the door frame twice inquiring if the sergeant had a minute.

Hank saw Kelly standing behind her and looked intrigued. "If representation from CFD is here, this must be good. Come in."

Erin closed the office door behind the two of them and they sat in front of Voight's desk.

"What brings you to our next of the woods, Severide?"

"Arson, sir. Or at least what my department believes to be arson. I told Erin but OFI is refusing to investigate due to insufficient evidence. Six adults and fourteen children have died in these fires. I can't let whoever is starting these fires get away with it."

"Fourteen kids? That's a lot."

"From what we've been told by the medical examiner, the three homes involved were foster families."

Voight looked to Erin. He had taken the girl in when she was 15 and problematic. She was now a phenomenal detective in his unit. Someone threatening foster families in his city was almost like they were threatening him personally. But he needed to hear from Severide what exactly CFD was looking for in this situation.

"And how can we help?"

"I'd like to look into it with assistance from the your team in order to present OFI with more evidence. I'd like them to be classified as arson and dealt with."

"And if we catch the person responsible in the midst?" Voight asked, his fingers steepled as he leaned back in his chair.

"Even better," Kelly answered without question.

Erin knew that Kelly understood that Voight had a very signature way of dealing with perpetrators of this nature. And she was pleased to hear that Kelly would look the other way if this arsonist was caught in the process of their investigation.

"Erin, you can work with Severide on this as your schedule permits. But we do have several open cases to tend to."

"Understood."

Voight turned his attention back to the squad lieutenant. "Severide, you know that foster families are something that are close to both Erin and my hearts. Let's put this asshole way."

Kelly nodded and shook the sergeant's hand. The detective and lieutenant stood up to leave the office, talking about plans to review the information that they had in their possession already.

"I'm going to send a team out the review the three crime scenes see if we can dig anything up. You around to meet tonight and start looking at whatever they come up with?"

He shoved his hands in his pockets and nodded, "Yeah, tonight's good."

"Okay, my place at 8."

Severide gave Erin's shoulder a squeeze before heading out of the bullpen and down the stairs. Erin could feel Jay's questioning gaze burning a hole into where Kelly's hand had just been. She felt like she owed him an explanation but whether it was as his partner or his girlfriend, she wasn't sure. Luckily, Hank took the decision out of her hands.

He stepped into the bullpen and called everyone to attention. "Erin's going to be working with Lieutenant Severide of 51 on a potential arson case during off hours. She's going to be focused on our open cases during shift. If she needs anything from anyone I'm sure she'll speak up, but I wanted everyone to be aware. Any questions?" When no one spoke up, he nodded. "Okay now let's get back to this crew that's using mail order brides to smuggle in smack."

The group resumed the case that had been put aside before lunch and worked well into the afternoon and evening. At 7 pm as things were just starting to wind down, Erin knew that she needed to start heading out the door to meet Severide at her apartment. As she packed up the arson case files that the scene investigators had given her on the crime scenes, Jay approached her desk.

"So what do you want to do tonight? Thai? Indian?"

"I can't tonight. I'm meeting with Kelly to start a review on the crime scenes."

Erin looked into his green eyes and immediately knew that he was not happy with the situation. She didn't think that he would be considering that she and Kelly had dated.

"Do you want another set of hands or eyes?" he asked.

"I think we'll stick with just the two for now." The hurt look that appeared on his face made her regret her answer. "I'll see you in the morning okay? I'll bring you a coffee."

He nodded solemnly and she stretched up to kiss him. Her mind wandered to thinking about how different Jay and Kelly kissed, which she immediately had to bury.

"Love you," she told him as she backed out of the bullpen and headed out to her apartment.

It didn't shock her that Kelly arrived early or that he came ready to feed her. He held a giant plastic bag filled to the brim.

"Thai Lagoon?" she asked as she sniffed the air. The scent of the fragrant Asian cuisine wafted out of the bag and caught her attention.

"I know you work better on a full stomach."

"What's that supposed to mean?"

"You get a little cranky when you're hungry. I figured I'd prevent that from happening."

She scowled at his keen observation of her and led him inside. He unpacked the bag as she got two beers out of the fridge. Erin smiled when she saw that he had gotten her favorite - Thai spring rolls and beef Pad Thai.

"You remembered?" she asked taking a swig of her beer.

"Hard to forget. You ordered it every time we went there."

She bit her tongue from reminding him that they had dated months and months ago. Ultimately it was sweet that he had remembered her food preference. She took the beers over to the table where she had the case files that the forensics teams had prepared for her as well as the information that Kelly had given her from the jump. Kelly brought the food over and listened to what she had to say.

"Forensics found evidence of an accelerant in each of the three fires. They haven't been able to identify the substance yet but they're working on it. If its something purchased maybe we can nail down who's been buying these items in such large quantities."

"Casey said the flames looked almost yellow when truck got there so most likely we're looking at gasoline being the accelerant. But we're going to need to have something else to go along with that – evidence of matches or homemade timing device."

Erin poured over the files and dragging her finger along the information that had ben prepared as Kelly looked over the crime scene photos.

"Oh," she said and that piqued his interest.

"What?"

"The team found a sizable hole in each of the roofs at the crime scenes."

Kelly grit his teeth at the information. "Bastard wanted the fires to have enough oxygen." Erin gave him a quizzical look.

"Any arson investigation will classify arson based on the fire triangle – oxygen, fuel source and heat. Putting a hole in the roof would allow the fire to climb through the house quickly and wouldn't be something the residents would realize. Did the team figure out how the person got in to the houses?"

"Basements - two windows and sub-ground door."

"He set it up perfectly. The accelerant in the basement so that the fire would take on a life of its own, we had no shot."

Erin could feel the anger radiating off Kelly and knew that she needed to calm him down before he flew off the handle. She was angry too but she knew that Kelly took this personally seeing as how he was a firefighter and he had been unable to combat the fires that had claimed so many lives recently.

She gently laid a hand on top of one of his clenched fists, hoping that the touch would ease some of his fury that he felt. The touch was electric. He looked up at her and she knew that he felt it too.

Clearing her throat, Erin removed her hand from his and reassured him with words.

"We're going to catch this guy. I can feel it. He owes us a mistake."