"Sam! Damn it, Sammy, where are you?" John Winchester shouted into the burning room. The smoke was getting thicker and thicker and he could feel his chest tightening as he struggled to draw in every breath. He was beyond worried about Dean - who was clinging onto his father like a young child - and Sammy, who was absolutely nowhere in sight. He looked at Dean, he was squinting to see through the smoke and his breaths were shallow, often accompanied by a cough or a wheeze.

"Dean, I'm going to take you outside, and then I'll come back for Sammy!" John hollered over the roaring of the flames and the crackling of the building's seeming frail structure.

"No!" Dean replied almost immediately, not to John's surprise. "I'm not leaving, Sammy. We have to find him first, Dad, he's all alone."

John stared into the soft green eyes of his eldest son, Mary's eyes, he couldn't risk losing two sons. He needed to make sure Dean was safe so he could find Sam.

"Not a chance, Dean!" John shouted. "I want you outside; even if I have to drag you out there kicking and screaming."

"I want to help look for Sam." Dean's gaze was hard and unwavering.

"No, how do you think Sam will feel if you get hurt looking for him?" There it was, the flicker of uncertainty, the unwillingness to cause Sam any pain. "We're wasting time, Dean. You can help search until we reach the fire exit and then I'm going alone."

Dean nodded, realising that this was the best offer he would get. He drew in another breath and felt a stirring of panic when he realised that he wasn't getting enough oxygen. John moved quickly, scanning every inch of the place that he could see for a small child, he kept thinking Sam was curled up in the corner before realising that it was only smoke. The fire escape was out of the question, flames licked at the floor and walls around the door creating a menacing shadow effect on the ceiling that was already a dark, sooty black.

"The front door." Was all that was uttered as the desperation to get at least one of his sons to safety started to overwhelm John. He could remember the way the flames had wrapped themselves around Mary all those years ago, the way she had screamed in agony as they scorched her skin that had been protected by a flimsy nightgown. "Hurry, Dean." He said, dispelling those thoughts with a shake of his head. Dean's face was sweaty with what seemed to be tears tracking their way down his cheeks through the black soot.

"FIRE DEPARTMENT! ANYONE HERE? CALL OUT!" A muffled voice shouted. John felt his heart jump at the words.

"We're here!" He shouted hoarsely, his voice strained from the smoke inhalation.

"Are you injured anywhere?" The fireman asked loudly.

"No, we're fine, but my son - my other son, is missing." John said quickly.

"Herrmann, Mills, take this man and his son outside, now!" The man shouted. "Severide, we've got to find the kid."

"Sam, his name is Sam." John said. It was shocking how he could confront ghouls and ghosts and werewolves without a flicker of doubt, but as soon as his son was missing and possibly gravely injured, he was reduced to a terrified mess. All he could think about was Sammy, he couldn't lose Sam, he was so innocent and pure.

"This way, Sir. Lieutenants Casey and Severide will find your son." Mills said, as he guided John Winchester to the front door. Herrmann moved towards Dean, helping him towards the exit.

Dean had other ideas. Once he saw the door, he knew that he wouldn't be able to do anything to help Sam, except wait for the firemen to locate him. He began to struggle, Herrmann had to adjust his grip so the boy didn't slip out of his arms.

"Come on, kid! We need to get you out, it's far too dangerous in there!" Herrmann shouted as the ceiling gave a loud groan.

"No! I can't leave without Sammy. He needs me!" Dean said, twisting and writhing furiously.

"He'll be ok, we've got men looking for him." Herrmann tried to convince him.

"No!" Dean snarled. "SAM! SAMMY!"

He had promised to look after his brother. The last time there had been a fire he had carried his baby brother out of the house himself, and he had taken responsibility for his little brother's wellbeing ever since that day. He refused to let Sam get hurt, he would do anything to help.

"Chief, we've got a problem, I'm going to need backup." Herrmann managed to shout into his radio whilst maintaining his hold on Dean.

"Copy that, Mills get back in there, Cruz, go with him." Chief Boden commanded.

Herrmann held tightly as he waiting for help. It didn't take long, Mills had known exactly where he'd left Herrmann.

"Jesus." Cruz muttered as he saw the wild teenager trying - and almost succeeding - to throw off a trained fireman.

"Grab him, he's trying to go ba-"

"SAM!" Dean hollered, cutting Herrmann off. "Get off me! I need to help Sam!"

Cruz and Mills jumped into action. Herrmann secured his arms, whilst Mills grabbed his legs and Cruz supported his torso.

"Sorry, kid, but we ain't gonna let you kill yourself in there today." Herrmann told the struggling teen.

"He sure is stubborn." Mills grunted.

"Dean!" John shouted as he saw his son being escorted out of the building by three firemen. "I told him not to go back." He said quieter, wincing as the paramedic did something that caused a burn on his back to sting and then throb.

"He seems stubborn." The paramedic murmured.

"Only when it comes to Sammy." John sighed. "Any other time he would do exactly what he's told, when he's told to do it."

"He's a good brother." The paramedic said.

"That's why I'm struggling to be angry at him."

"Casey, Severide, the smoke is turning black. You have one minute and then I want you out!" Boden said sternly, wincing as the man's other son heard him and started going crazy.

"Don't you dare leave him in there!" Dean shouted.

"Dean." John said sternly, using the tone of voice he would do on a hunt. Dean stilled, looking at his father. He was quiet, but John could tell it wouldn't last, especially from the thrusting forward of his chin and the narrowed eyes. "Let the men do their job, if you stop trying to run into a burning building, they can focus on finding Sammy."

"Yes, Sir." Dean practically snarled, but remained in place. Mills stood by him in case he decided to make a break for it, while Cruz and Herrmann jumped into action, speaking lowly into their radios.

"Chief, we've found a kid. He's unconscious, but we think it's the one." Casey's voice pierced the air.

John thought he would collapse in relief; they'd found his boy.

And there he was. Two firemen were leaving the building, his son was in the arms of the blond one. His sweet, baby boy. Sam's face was slack in his unconsciousness and his skin and clothes were coated in the same soot that covered John and Dean, but it didn't matter, his sons were fine.

Disclaimer: I don't own Supernatural or Chicago Fire.

There weren't any CFxSPN fics so I decided to write my own. I hope you like it, I'm not sure if I'm going to add anything more to this, I might because I have a few ideas where it could go.

Set in Season 1 CF, no specific time frame though, and set pre-season 1 SPN.

Thank you for reading.