My take on how the second episode of 4 season could progress from the scene, where baby Derek showed Stiles against the door. Mostly headcanon, because OMG time travel!

I'm surprised nobody thought about this small idea yet, or maybe I'm wrong (I'm only reading Sterek fics) and there are fics with this. Anyway there. I hope you'll be surprised at the end.

Can be read as Stiles' and Derek's friendship or Sterek. Whatever you prefer.

WARNINGS: A few swear words.

DISCLAIMER: I don't own Teen Wolf and it's characters.

"Okay, I didn't lie!" Stiles defended as Derek shoved him face first into closed door of Scott's room. "I omitted certain truths." Derek pressed closer and Stiles added quickly, "Vital truths, now that I think about it."

Suddenly Stiles was free to move. Figuring he didn't need to worry about being mauled by the angry little Derek he turned around to explain and blinked in disbelief at the scene.

Disgruntled Derek, adult Derek, was holding his struggling younger self by the scruff of his neck, easily keeping him from lunging back at Stiles.

"Let go of me!" young Hale demanded.

Derek just leaned closer to him and growled, flashing his red eyes. The boy instantly stilled, eyes wide in awe.

"That's..." Stiles trailed off. Because what the hell? How come they had two Derek's now? And one of them an Alpha. And now the red eyed glare was directed at him. Great.

"Stiles," Derek the Alpha demanded. "What's going on?"

"How should I know?" the boy in question sighed.

"You lied to me!" young Derek accused. "You told me my family moved away!"

"That's not technically a lie."

"If..." the Alpha Derek said hesitantly, looking almost hopefully at his younger self. "If we tell him about the fire..."

Stiles suddenly found it hard to breathe, tears stinging in his eyes. It wasn't fair. Why couldn't it be so simple? "Dude, no," he managed to choke out, feeling like the biggest asshole in the world for crushing that hope in Derek. "I'm sorry. But it's not... He's magically deaged. He's supposed to be twenty something." Stiles took his eyes from the disappointed Alpha and looked at the younger teen. "We're going to fix this. And yes, we didn't tell you about the fire. We wanted to spare you that pain for however long we could."

Young Derek nodded, slumping on the bed, all the fight and anger drained out of him.

"As for you," Stiles looked back at the adult Derek. "Let's go with the time travel theory. When are you from? And please, events will be easer than dates."

Derek hesitated. He opened and closed his mouth a few times before he managed to utter just one word, that had Stiles on the verge of crying again, "Boyd."

Stiles gave in to the instinct and moved to wrap his arms around the Alpha, "It wasn't your fault."

Almost instantly Derek pulled away gently, shifting uncomfortably, "You said that already."

"And I say it again. And again. Because it's the truth. It wasn't your fault."

Derek nodded, looking down at his feet.

Stiles sighed dramatically, "What is my life? I got stuck with two emotionally stunted werewolves."

Adult Derek smirked slightly. Stiles counted it as a win.

"You're an Alpha," younger Derek piped up.

"I am," Derek agreed.

"They didn't tell me there is another Alpha in town," the teenage werewolf grinned. "You're hot. Wanna go out?"

There was silence. Young Derek stared at his older version with a bright smile. The Alpha stared back, eyes wide and jaw dropped. Stiles choked out a snort, tears in his eyes again and doubled over, reaching frantically for his phone. He dialed Scott, who picked up after the first ring. Shocking.

"Stiles?" the teen Alpha asked after a moment of silence.

"S-Scott," Stiles gasped. "Oh my God, Scott."

"Stiles!" Scott sounded more worried with each passing moment. "Are you okay? What happened? Stiles?"

Stiles couldn't answer focusing instead on not choking to death. Adult Derek rolled his eyes and plunked the phone from his hand.

"He's fine," he growled.

There was silence again and then Scott asked, disbelieving, "Derek?"

Derek huffed, looking down at the laughing teen, "Stiles, breathe."

"Derek? What's going on? What's wrong with Stiles?" Scott demanded.

"He's being an idiot," Derek sighed long-sufferingly.

Young Derek's eyes widened as he finally figured out the situation.

"Scott," Stiles wheezed, using adult Derek as a crutch to pull himself back upright. "Little De-Derek," he fell to the floor again, laughing hard. "He hit on himself!"

"What?" Scott asked in confusion. "Anyway, it doesn't matter. Derek, we think she's coming after you."

Derek frowned, "Who's coming after me?"

Abruptly Stiles sat up, completely serious.

"Gimme that," he wriggled his fingers at the phone and the Alpha handed it to him. "What did you find out?"

"Peter thinks she wants something from Derek. That's why she turned him into teenager when he still trusted her."

Stiles looked at the teen in question staring at them in confusion, "Any idea what she wants?"

"No. But it doesn't really matter anymore since he's back to normal."

"He's not."

"What? But-"

"Where are you?"

"We're leaving the loft right now and coming to you."

"No!" Stiles protested. He didn't know how Scott will react to another Alpha and he wasn't subjecting himself to the fallout of that meeting if he could avoid it. "Don't. Stay away. Try to intercept her, but don't come here."

"Why?"

Stiles looked at both Derek's, "It's complicated. But trust me, we'll be fine. I have to go. Keep me informed." He hung up.

"You're me," the teenage werewolf stared in amazement at his adult version. "An Alpha. Wow."

Derek sighed. Why he must be constantly surrounded by teenagers?

"Well isn't that interesting?" Stiles asked. But it was wrong. Stiles was in front of him, and the voice was coming from behind. He whirled around.

Stiles was sitting on the window sill, smirking. He was unnaturally pale, had dark circles around his eyes, his eyes was much darker than usual and he felt and smelled off.

"You!" Stiles, the right one, hissed. Derek glanced at him as he smelled pure terror coming off of him. Young Derek already by his side, hovering protectively.

"I came in peace?" the wrong Stiles raised his hands non-threateningly.

"Y-you can't be here," Stiles said desperately. "We killed you!"

The wrong Stiles rolled his eyes, "I'm sure you did. But now I need your help."

"My help?" Stiles asked incredulously. "Are you fucking serious?"

"You need to send me back to the time I came from. And believe me, if I learned something over the thousand of years is to not to screw with time travel around."

Stiles made a distressed sound, apparently lost for words.

"Who are you?" Derek the Alpha growled.

The wrong Stiles looked him up and down curiously, "You're obviously from further back than me. I'm Nogitsune."

"Nogitsune," Derek spat in distaste. He narrowed his eyes, "And you possessed Stiles."

"Yeah, whatever," Nogitsune shrugged dismissively. "Apparently not for long," he hummed thoughtfully and looked straight at Stiles, who flinched. "If I submit to Alpha Hale will you help me?"

Stiles frowned, "Why would you do that?"

Nogitsune rolled his eyes, "Now you're just being difficult. He's our Alpha."

"He is?" Stiles was honestly confused.

"Whatever," Nogitsune sighed and pulled himself into the room. He stood straight and bared his throat in submission, "Alpha Hale."

"Nogitsune," Derek growled back, his eyes flashing red.

The trickster clapped his hands, "Now, back to the case." He gestured at young Derek, "I see you have an interesting situation."

"Yeah, you know what?" Stiles threw his hands up. "We're not doing this here. We'll go to Deaton. Derek, young Derek I mean, you come with me. You two go out through the window like the creepers you are and meet us at the jeep."

"Soo," little Derek drawled from the back seat, where he was sitting with his older version. Stiles was driving, despite the worry the Alpha expressed at his ability to get them safely to their destination. Sure, he was shaken by the abrupt appearance of the time travelers, but whatever. He could deal. He will deal. He was fine.

"Kate Argent is back," Stiles blurted.

"What?!" Derek and Nogitsune growled in unison.

"Kate?" young Derek asked helpfully. "She could hel-"

"No!" Stiles snapped. "She's the one who burned your house down with your family inside and did this to you."

"She wouldn't!" little Derek protested.

"She did!" Alpha Derek looked at his young self beside him. "She fucking used you- me to get to the house and killed them!" That seemed to stop any further protest from the young werewolf. "But she's dead. She's supposed to be dead. How did she came back?"

"Apparently you can get turned by the scratch," Stiles answered. "And Peter clawed her pretty good."

"So she's a werewolf now?" Derek frowned.

"I don't know," Stiles sighed. "We actually haven't seen her yet."

"So how do you know it was her?" Nogitsune asked.

"Because of him," Stiles nodded back at the younger Derek. "We went to Mexico to find him. We were convinced the Calavera hunters got him, but they told us it was Kate. We found him like that in an Aztec temple in the middle of nowhere."

"Oh," Nogitsune paused. "In the city destroyed by an earthquake?"

"Yeah," Stiles glanced at him. "How do you know that?"

"I might have something to do with that earthquake," Nogitsune shrugged. Stiles gaped at him.

"Stiles!" Derek barked from the back. "Watch the road!" The teen snapped his head forward, clenching the steering wheel tightly.

"That's pretty powerful stuff you're dealing with," Nogitsune commented.

"Do you know how to reverse that?" Alpha Derek demanded.

"Maaaybe," Nogitsune smirked.

"You-" Stiles started, but was cut off by his phone ringing. He fumbled for it and tossed it back at the adult Derek.

"It's Scott," the Alpha said and answered the call, putting it on speaker. "What?"

"Lydia and Kira found a dead body, torn to shreds. We think Kate did this. Peter has a theory that Kate wants to learn how to control the shift, so she turned Derek into teenager so he could give her the triskelion? Sounds important and something she shouldn't have."

Derek snorted. He couldn't help it.

"What? What?" Stiles asked wanting to know.

"Peter's laughing too now," Scott grumbled. "What's so funny?"

"What Kate wants," Derek chuckled, shaking his head, "is an object my mother used to teach us control the shift. She made us believe it had special properties helping us stay focused. In reality it's just a toy."

"Really?" young Derek sounded disappointed.

"You've got to be kidding me," Stiles exclaimed. "All of that for a piece of junk?!"

"Keep your eyes on the road," Derek reminded him.

"What?" Scott asked. "Where are you going?"

"To Deaton's," Stiles said, reaching for the phone. Derek frowned, but let him have it. "Try to find Kate. Do not come by. Bye, Scott."

"Why did you start to avoid Scott?" younger Derek asked curiously after Stiles ended the call.

"I'm not," Stiles huffed, like the concept of him avoiding his best friend was ridiculous.

"That's a lie," the Alpha said. "Stiles?"

"Look, you're an Alpha. Scott's an Alpha. I'm not looking forward to a pissing fight between you two. I have enough to deal with without it."

"Are you afraid of Scott?" Nogitsune asked incredulously.

"What?" Stiles slammed on the breaks and whipped to stare at the trickster. They were lucky the road was empty. "No!" It wasn't a lie, but werewolves could tell Stiles was nervous.

"Because I stabbed him with a knife?" Nogitsune scoffed.

"It was a sword," Stiles corrected and now smelled of guilt. "And no."

"Because the little tricks I did?" Nogitsune persisted. "The trap for coach? The fake bomb in school bus?" The more Nogitsune talked, the more Stiles got worked up, grief and guilt pouring off of him in waves. "The real bomb at sheriff's station? The hospital? The Eichen House?"

"I killed Allison!" Stiles yelled, startling everyone in the jeep.

"Okay, that's enough," Derek decided. "Nogitsune, shut up. Stiles, get in the back, I'm driving. No arguing."

Stiles nodded and fumbled for the door handle. His hands were shaking. His whole body was shaking. His vision was blurring. He climbed into the back seat and teenager Derek pressed his side firmly against Stiles'. Nobody said anything for the rest of the way.

"Wow," was the first thing Deaton said as he saw them enter into the back room they usually hung out at the clinic.

"Is this 'wow' the one I'm hoping for this time?"

Deaton smiled, "Yes, Stiles. I think I might know what's going on this time."

"Great! By all means, enlighten us."

"Seriously?" Nogitsune muttered, face-palming. "Still?"

"You're not going to cause any mischief, right, Nogitsune?" Deaton smirked.

"I submitted to Alpha Hale," Nogitsune answered and mumbled under his breath. "And those idiots still didn't get it."

"Excellent," Deaton looked around. Nogitsune remained by the door, leaning on the frame. Young Derek hopped up on the examination table at the center of the room. Adult Derek leaned against it's edge. And Stiles hid between them on the other side of the table. "Mind telling me from when are you from?"

"Definitely after you poisoned me," Nogitsune smirked. "Does it matter?"

"No, I suppose not," Deaton shrugged. "How are you feeling, Stiles?"

"What?" The teen in question looked at him in confusion. "I'm fine."

"I'm sure you are," Deaton soothed. "Let's try it another way. How did you feel after Nogitsune?"

"Half dead, tired, guilty like hell, depressed, crazy, panicked, freaked out, desperate, sad, and so on," Stiles snorted. "Take your pick."

Deaton rolled his eyes, "How did you feel, when you discovered, that Derek is missing?"

"I-" Stiles frowned, thinking. "I was worried, obviously. And-"

"No, you're over-thinking this," Deaton interrupted him gently. "Say the first thing that came to your mind. How did you feel, when you discovered, that Derek is missing?"

Stiles licked his lips, scratching at his neck. He looked around, noting how everyone were watching him intently. He sighed in surrender, "Like I couldn't breathe."

"How did you feel, when you found Derek?"

"Relieved and... disappointed?" Stiles sounded surprised. "Why would I be disappointed?"

"Now, how did you feel, when Derek from the past appeared?"

"Calm. I mean," Stiles flailed. "The current situation is crazy and it gets all deserved dramatics, but I feel calmer. And safe."

"There you go," Deaton smiled. "We have the whys. Now the hows."

"Wait," Stiles stilled, gaping at him. "Are you saying Derek is here to... make me feel better?"

"Oh my God," Nogitsune groaned and hit his forehead against the door frame.

"Essentially, yes," Deaton ignored the fox. "Through the sacrifice you three connected to the Nemeton. Because of your spark, you've made a deeper connection. But about that you should talk to Derek, when you get him back to normal, since apparently you didn't, otherwise you would know all of that. The thing is, Nogitsune's power affected your spark and it lashed out. Not violently for obvious reasons, but instead it gave you what you needed at this time: protection and answers to your current predicament."

"So what? I brought Derek and Nogitsune forward in time?"

"That's exactly what you did," Deaton nodded. "Time travel is not to be taken lightly. Changing even the smallest detail could end in disaster."

"That's why you need to send us back as soon as possible," Nogitsune chimed in.

"How?" Stiles threw his hands up. "Besides you're here to give me answers, but you didn't say anything remotely helpful yet. Wait." The teen whirled on Deaton, "If they learn here what happened, they could change something in the time they came from."

"Unlikely," Deaton shrugged. "Time travel forward usually comes with forgetting the travel the moment the person is back in a proper time."

"Oh. So if I accidentally slip how we killed Nogitsune, we'll still be able to pull our divine move in his time, because he'll forget I said how we killed him?"

"Yes."

"Okay," Stiles gestured at young Derek. "So, what do we do to fix him?"

Nogitsune sighed, "From what I gathered the ritual to deage him was specifically made so Kate could get what she wants. So when he give her the triskelion, the spell should lost it's effect."

"And then what?" young Derek asked. "You'll kill her?"

The rest of them shrugged.

"I'm all for that," Stiles said slowly, a plan forming in his head. "But maybe I have a better idea."

"It was a brilliant idea," Derek said quietly to the boy sprawled next to him on the couch.

"You think so?" Stiles asked nervously. "What if he won't like it?"

"He will," Derek assured him.

The plan went on without a hitch. Teenager Derek lured Kate, where they wanted her, gave her the triskelion covered in kanima's venom and bam! they had adult Derek back. Then they proceeded to dispose of her, hopefully permanently. And then Stiles was able to send Alpha Derek and Nogitsune back to their times. Now there was one more thing left to do.

They waited in Stiles' living room for the Sheriff to come home. Stiles fidgeting more and more as the time for Sheriff's return came nearer.

"Calm down, it'll be okay."

Stiles sighed and shifted slightly to lay his head on Derek's shoulder.

"You know," he pouted. "They could have just told me you're my anchor."

Derek chuckled, "They did."

"Well, they should be a lot more clearer about it."

"I think they were pretty clear," Derek smirked.

"Oh shut up, I was preoccupied with other things. Like," Stiles shuddered, "Nogitsune being there."

"He's not coming back," Derek nuzzled the top of his head in comfort. "And even if he does, we know how to fight him."

"Okay," Stiles said quietly.

"Your dad is home."

The teenager chuckled, "I hope he wasn't serious about driving him to the Eichen House."

The front door opened and the Sheriff stepped in. He caught the sight of the two boys and froze for a minute.

"I don't want to know," he groaned finally.

"Hey dad," Stiles grinned. "You maybe want to grab a drink. We need to talk."

About an hour later the Sheriff, to his utter dismay ("Time travel is real, dad."), was filled in on the recent happenings.

"Do you even know where to go?" he asked, when they got to the last part of the plan.

In answer Stiles slid his phone to him. The Sheriff glanced at the text displayed on the screen.

"Okay then. It's not like I could stop you anyway."

"Thanks, dad," Stiles grinned. He jumped to his feet excitedly, "Let's go, Sourwolf!"

"And Stiles?" the Sheriff smiled. "I'm proud of you." He looked at Derek, "both of you."

Derek ducked his head, "Thank you, sir."

"Aww, you made him blush," Stiles laughed. "That's adorable."

"Shut up, Stiles," Derek growled.

"Make me!" the teenager challenged and ran out of the kitchen, where they were having their conversation.

Sheriff threw Derek an amused look, "I hope you know what you're getting yourself into."

The doorbell echoed through the apartment. The man sighed and heaved himself up. He wasn't expecting any visitors and his charge was at school at this time of the day. He pulled the door open and blinked.

Derek Hale was practically buried under all the bags he was carrying. Next to him stood Stiles Stilinski, shuffling his feet awkwardly.

"Hey, Mr. Argent," the boy greeted. "So, I know it's not ideal. And I can't ever make up for what I did. And it won't replace Allison, or your sister, or anything. But, maybe, you could start over?" With that he gently shoved a bundle he cradled in his arms into hunter's.

Chris looked down at the baby uncomprehendingly.

"Uh, well, long story short. Kate came back and we didn't want to kill her, but we couldn't leave her to her own devices either. So we let her taste her own medicine and, well," Stiles waved at the baby.

Chris stared at the little girl in his arms. He could see his sister in her. And now she could have a second chance at normal life, not being a coldblooded killer. And he a second chance at having a daughter.

"Mr. Argent?" Stiles asked hesitantly as the silence stretched past the few minutes.

The hunter raised his eyes to the werewolf, who suffered the most by his family and yet still was able to make such a kind gesture toward his nemesis. To the teenager, who wasn't responsible for anything Nogitsune did, but still felt guilty and responsible and needed to make everything better.

"Thank you," he said and let them in.