Disclaimer: I don't own any of the characters from Teen Wolf they belong to their creator. I own Lexi Lahey and anything/anyone else you don't recognise.

Let There Be Light

"This is stupid," Derek huffed crossing his arms as his younger sister Cora stood directly in front of him. "Do they know what they're getting into?" They were standing in the entrance of the Beacon Hills Bowling Alley.

"Hey Derek," a voice said from behind Cora, one that Derek hadn't heard in a couple of years. "Of course I know," he could tell that she was smiling but couldn't see it. "Hey kiddo,"

"Hey Lexi," Cora grinned spinning around and racing over to the older girl before dragging her over to Derek. "Lexi Lahey remember her?" Cora questioned before she started backing away. "Lexi...he's..."

"I know he's a stubborn ass, sweetheart. Go, go have that date with my kid brother," Lexi smiled at her before she returned her attention to Derek and uncrossed his arms. "No need to be all huffy, I know you're dying to do it again. So go ahead," Lexi took Derek's hand and guided it towards her face.

"Lexi? What are you doing here?" Derek questioned, raising an eyebrow at her as he moved his other hand towards her face as well. "I remember what you look like, or looked like," Derek muttered, before Lexi held her hand out for him and waited for him to take it before pulling him towards the front door. "Lexi?" he stumbled over his feet as she hadn't let him grab his cane.

"Relax, I've got it. We're just going out into the rain for a moment," Lexi said there was a smirk evident in her voice. "Listen to the raindrops as they hit my face, and concentrate...wolf-boy," she whispered the last part as people passed by them.

Derek and Lexi stood in the rain, with Derek's hand not leaving Lexi's face as his eyes glowed blue and she flashed hers a golden orange. Lexi had been bitten by Laura, her best-friend and Derek's older sister at the age of seventeen but she'd known the Hale's since her first day of school. The last time Derek had seen her before he'd gone blind was when she'd returned just after he'd turned her little brother to save him from their father. That was four years ago, she'd been back twice since then - the first time just after he'd gone blind he'd rejected everyone except for her and Cora.

"How long are you back for?" Derek asked, smiling as he took in what he could see with his wolf-eyes the rain hitting her face had created somewhat of an aura around her.

"As long as you want me back for, I have no immediate plans plus Cora's here and it defeats the purpose of being away," Lexi shrugged taking Derek's hand as the rain stopped and guiding him down to her car. "Cora and Isaac will be a while, so you're stuck with me,"

"You know McCall's going to want to see you again," Derek said, as he let her guide him towards the car. "Where are we going?"

"I know, and there's an open house that I want to look at in an hour...and you're coming with me," Lexi said as she opened the passenger door for him and helped him before handing him his cane. "You know, I couldn't have helped you when it first happened," Derek growled at her as she climbed in the car, knowing what she said was true. "Are you still refusing to learn to read Braille?"

"Fine and yes," Derek was abrupt when he answered her, crossing his arms over his chest and tightly gripping his cane.

"Der, relax...when we get there don't let go of my hand. I know it sounds weird but trust me okay?" Lexi questioned, as she started to head towards the location of the house that she was planning on looking at.

Derek and Lexi didn't get very far when she heard an all too familiar roar and looked at Derek, he'd heard it too and neither of them liked the sound of it. Lexi headed in the direction of the roar and wasn't surprised when it lead them to preserve, nor was she surprised to see Scott McCall, and his pack.

"Lexi Lahey? What are you doing here?" Scott questioned, pulling up next to the drivers side before he realised that Derek was in the car with her. "And with Derek?"

"My kid brother's on a date with Cora, or well was on date...can we just go find them?" Lexi questioned getting out of the car and walking around to Derek's side. "He'll be fine with me, go!"

"Liam stay with them," Scott said before he took off running, going wolf while he was at it.

"Sorry kid, I'm not staying here. Derek, remember what I said? Don't let go," Lexi grinned as they felt the rain pelt down on their bodies before they took off running. "Also we are so going to need to change before we go to the open house,"

"Lex!" Liam yelled trying to keep up with the two older wolves, Derek was still surprisingly agile for someone who couldn't see. "Slow down!"

"Fuck off Liam!" Lexi yelled as she smelled the air and suddenly stopped, Derek felt her stop and stopped himself from bumping into her.

"What is it?" Derek questioned, before he smelled what she was smelling. "Wolfsbane and belladonna?"

Because both Lexi and Derek had stopped running Liam came crashing into them sending them straight to the ground which was a good thing as all of a sudden there was bullets flying at them. Lexi still had a hold of Derek's hand while she did a little something unexpected. Lexi was part witch, which was something that only the Lahey females inherited.

"Stay still," Lexi said quietly as she looked around her eyes glowing golden briefly before they turned purple she grinned looking at Liam. Lexi held up her free hand and touched her index finger and middle finger to her thumb letting a purple orb grow between them until it was roughly two inches wide before she flung it in the direction that the bullets had come from. "You two okay?" Lexi looked at Derek and smiled his eyes were still glowing blue and he could vaguely see the outline of her face.

"I'm good," Derek said before Lexi's attention turned to the beta beside them.

"I'm good, too...Sorry," Liam muttered, as Scott and Malia reached them. "What even was that?"

"Don't worry about it," Lexi smiled while she pulled Derek up with her as she stood up.

"You guys okay? We heard the gun shots," Scott said as he pulled Liam up and the three of them looked at Lexi. "The lights new,"

"New to you, but not me," Lexi shrugged, not letting go of Derek's hand as she spoke – he may have grown up in the preserve with her but not seeing it and not being in it for so long was new. "We don't have much time, did you catch their scent?"

"Yeah, and then we lost it. Why'd you stop?" Malia asked, her eyes darting around before they landed on Derek and Lexi's hands and she noticed that Derek didn't have his cane with him.

"Belladonna and Wolfsbane," Lexi answered before turning her attention back to Derek and noticing that he wasn't listening to them any more. "Der, what is it? What can you hear?"

"I can't hear anything," Scott raised his eyebrow at Lexi and then at Derek who he noticed had tightened his grip on her hand. "Derek, direct us?" Scott questioned, Derek yanked Lexi's hand forward before he said anything.

"Head towards Hale house,"

Scott, Malia, Liam, Lexi and Derek took off running towards Hale House as whatever Lexi had done to stop the hunters from hurting them slowed down. The rain started beating down harder which made it harder for Derek to navigate where he was so they stopped running for a second. Liam confused as to why they had stopped, Malia put her hand on Derek's shoulder only for it to be roughly pushed off. Lexi moved so she was standing in front of Derek instead of behind him.

"Der, I want you to try something. Focus on Cora's voice and only hers ignore everything else," Lexi closed her eyes briefly forcing them to change from golden to purple as she put her hand to Derek's ear. "I'm filtering everything but my voice and Cora's okay?" Derek nodded before he answered her.

"Can you do that all the time? The noise hurts my brain," Derek muttered the last part of his sentence hoping that only Lexi would hear him.

"Not all the time, but when I'm around I can okay? Now which direction are they?" Lexi said before they were off again with her slightly in front smelling the air for any trace of Isaac. 'Come on little brother, where are you?' Lexi prayed that her brother could hear her like when they were kids.

Meanwhile Cora had clung to Isaac the second that they'd been taken. She may have been tough on the outside but spending six months as a hostage as a teenager, this was bringing back memories that she didn't want. Isaac had held her as close as he could until they'd be separated and then he could only hold her hand.

"They'll find us," Isaac said before he roared out in pain again as he felt the wolfsbane laced knife slice against his thigh.

"You don't know that," Cora mumbled holding his hand tighter than before.

"Yes I do," Isaac mumbled taking a deep breath as they stabbed Cora in her side forcing her to roar in pain. 'They want the blind wolf...' Isaac was silent hoping that Lexi had heard him. 'They want Derek, keep him away,'

'Isaac...where are you?' Lexi questioned, she'd heard him and stopped running making Derek stop too. 'I've got Der with me, and Malia, Scott and Liam,'

Lexi touched the side of Derek's head gently and allowed him to hear Scott's voice, and slowly the others and every surrounding sound. Doing it too fast would overwhelm him, and they couldn't have that. Scott raised his eyebrow wondering what she had done before they found themselves ducking again.

"Guess that means, that they're in there," Scott said as they laid on the ground and Lexi shot a purple ball of light into the air. "I'll text Argent, Peter and Theo for back up," Scott pulled out his phone as Liam continued to stare at Lexi. "Liam, stop," Scott hissed snapping the younger boy out of it.

'Isaac...how many are there?' Lexi asked, letting go of Derek's hand only the second she did she found him grappling for her shoulder. "Easy Der, I'm still here,"

'At least a dozen,' Isaac answered, trying to hold back from roaring again as he watched the black lines go up both his and Cora's arms they were helping each other and they didn't know how.

"We saw the light," Peter said as he all of a sudden turned up with Theo and Argent close behind him. "What was that?"

"Lexi Lahey," Derek said as if it explained everything, his hand still on Lexi's shoulder as she motioned for them to get down to.

"Ahh Lexi, so you're the beta that my niece turned," Lexi shot Peter a glare as he spoke before she motioned that his other niece was behind the chained fence.

"Scott, who do you trust the most to keep Derek safe?" Lexi asked, running a hand over her face as she spoke her eyes still glowing purple. "Der, it's okay – they'll need me and they can't risk you getting taken," Lexi said as she felt Derek's grip tightening on her shoulder and his claws digging in. "Der, I'm still right here," she took his hand in hers and squeezed it.

"Stiles...but he's at the clinic with Deaton, Mason and Corey," Scott answered, and before they knew it Lexi and brought Stiles to them.

"What the hell?" Stiles exclaimed, Derek almost instinctively covered his ears as it was ear-piercing.

"Sorry, my fault. But we need you to stay with Derek," Lexi said holding up her hands with Derek's still in her left hand. "Der, take Stiles' hand he's going to protect you,"

Hours later and they had rescued Cora and Isaac and taken them back to the clinic for Deaton to examine, he was just as surprised as everyone else at the return of Lexi. Now that Lexi was back in town Derek was ignoring Stiles and no one could work out why. Deaton may have been acting surprised to begin with but he knew the reason that Lexi was back, he'd asked her to come back to help. Peter had disappeared to who knows where.

"I just have one question, has anyone left Derek alone for more than say half an hour at a time?" Lexi questioned, pulling her curly purple hair back into a pony tail. "Stiles stop the tapping already," she hissed glaring at the younger man as she watched Derek's eyes darting around the room. 'You okay? It's okay, you don't have to say anything out loud,'

"Uh..." Scott stumbled over what to say while Stiles continued his tapping.

"Stiles! Enough, please?" She asked again, this time walking over to Derek and moving her hand to his ear again. "Der, I'm going to filter out the background noises, it should make it easier,"

"I have...for like an hour but that's it..." Stiles said, as he watched Lexi's every move to see exactly what she was doing to Derek. "What are you doing?"

"Filtering out the background noises, if you haven't noticed his eyes were darting around the room like they were searching it out...with Derek being blind every single little noise is amplified," Lexi explained, though she vaguely remembered explaining it two years ago and telling them that they had to give him space but clearly the latter hadn't happened.

"Oh...Why didn't you say anything?" Scott questioned, turning his attention to Derek as Deaton finished burning out the wolfs-bane from Isaac's injuries.

"I did, you didn't listen," Derek snapped, turning his head in Scott's general direction as Lexi pulled her hand away and moved over to Cora and took hers.

"Yes I did," Scott said almost too quickly as though he hadn't thought about his actual answer. "Okay so I listened...but didn't act...Sorry,"

"We're all sorry, we had no idea," this time it was Lydia who spoke, her voice more gentle than the others had been.

Isaac looked at Lexi and reached for her hand grabbing it the second it was inches away from him and pulled her between him and Cora. Lexi watched as the veins in her arm pulsed black as she took the pain from both Cora and Isaac. No one had seen anyone take it from both. Deaton smiled nodding at her before he went to Cora and started burning the wolfs-bane from her wounds.

"What else did you say could smell?" Deaton questioned as Lexi took her hands from both of them, and her fingers started glowing purple. "Lexi?"

"Belladonna. To cure belladonna poisoning we need to flush their system," Lexi said, before she motioned for her bag there was some things that she kept on her all the time. Stiles grabbed it and handed it to her again watching what she was doing. "Stiles, you may be able to help," Lexi smiled pulling out a small vial of amethyst powder, and then one of rose quartz and a final one of emerald powder. "Mix these together with some water, it'll make a cup all up," Lexi paused before she added. "Mix them in the order I gave them to you, add the water last,"

"What happens if he mixes them in the wrong order?" Scott asked as Stiles took the three vials over to the sink and grabbed Malia went to grab a cup.

"Well that could be deadly, so Stiles. Amethyst – purple, Rose quartz – pink and then the Emerald – green," Lexi repeated, Stiles did as he was told as Lexi helped Cora to sit up before helping Isaac. "You good sweetheart?" Lexi asked wrapping her arms around Cora and hugging her while Cora nodded before she turned around and faced Isaac.

"I think mom was lying," Isaac said all of a sudden as he looked at his sister, she tilted her head to the side wondering what he was talking about before she looked down at his fingers.

"When?" Lexi asked, taking his hand in hers and looking at the small purple sparks. "Tell me what you're thinking about?"

"Yesterday...and Cora..." Isaac said his voice barely above a whisper before he was hugging his sister. Isaac glanced over her shoulder and noticed that Derek had a slight smile, he'd heard him.

Stiles stood at the sink and mixed the crystal powders exactly the way that the older girl had told him to. Lexi let out a laugh, she knew what had triggered the magic residing inside Isaac. Lexi glanced at Stiles and watched as he powder the water into the powders and quickly remembered that he had to do one last thing.

"Counter clockwise! And then clockwise!" she exclaimed moving to grab them from him but stopping and watching as they changed colour while he stirred. Lexi smiled, Stiles blinked not believing what was happening. "And that's your little spark going into action,"

"Wait so it's meant to do that?" Stiles questioned, raising an eyebrow as the mixture settled into an aqua.

"Yeah, anyone with even the little bit of magic in them can do it," Lexi said before she held her hand out for Derek to join them. 'Der, try something. Close your eyes and let your wolf eyes take over,' Lexi watched as Derek closed his eyes and then opened them revealing his blue wolf eyes.

"Lexi?" Derek raised his eyebrow at her, and found his way to her hand. "How did you?"

"Know? Just a feeling, you can see clearer than before yeah?" Lexi said as he took her hand, he nodded closing his eyes and opening them again with his eyes returning to green. "Stiles can you split the mixture into two cups and give one to Isaac and one to Cora?"

Midnight they'd gotten to the loft, and by around 3AM Lexi was laying on Derek's couch, she'd stayed there the night as had Isaac. Cora was in her room, while Derek was in his with Isaac laying on the second couch. Derek had asked her to stay, she'd only said yes on the condition that she stayed on the couch. If she was being honest she wanted to see how he navigated around the loft with extra people. As Lexi was laying on the couch she heard a crashing sound coming from Derek's room and then nothing.

"What was that?" Cora questioned, sticking her head out of her room as both Lexi and Isaac sat up and looked at one another.

"I'll check, you two go back to sleep," Lexi yawned standing up and wrapping the blanket around her body. "Isaac, I don't care if you sleep with Cora, and Der has no say," she added, watching just how fast her younger brother was on his feet and stumbling his way into Cora's room.

"Night Lexi," Both of them said watching as Lexi made her way into Derek's room.

"Derek?" Lexi yawned, looking around the room and seeing only a tangled mess. "You want some help?" she questioned again, this time closing her eyes and opening them to reveal their golden wolf state.

"Hmmpf," Came Derek's reply from somewhere underneath the blankets and then a hand. "Please?"

"I'm coming," Lexi said, as she managed to climb over Derek's bed and reached through all the blankets to pull him up. "What happened?"

"Nightmare, not the one I've told you about," Derek answered, as he found her hand taking his and then felt himself being pulled back into the bed.

"Tell me about it, it may give me an idea on how to help you," Lexi said as Derek made himself comfortable on his bed and then pulled her back towards him. "You know Laura would kill you if she saw us,"

"Screw Laura," Derek muttered as Lexi settled in beside him and he pulled her closer but not before she pulled the blankets back on the bed. "I haven't told anyone...couldn't exactly tell Deaton or Scott but Scott figured it out,"

"Just relax and tell me about it," Lexi said as she intertwined her fingers with his and he hugged her tighter.

Derek took a deep breath before he relaxed enough to talk about what had happened. From what Lexi understood she'd gotten back into Beacon Hills an hour after Scott had found and taken Derek to the vet clinic. Derek went into detail saying that there'd been a combination of bright lights, something being thrown and hitting his face, and then being knocked out. He'd been out for at least five hours before Scott had found him. Lexi thought for a second before allowing her fingers to glow purple lighting up the room.

"Der, look at me. It's okay," Lexi said as he let go of her hand and brought his up to her face again. Derek closed his eyes and opened them his blue wolf eyes looking at her. "There you are," she smiled sleepily causing him to smile back at her.

"What are you thinking?" Derek yawned before his eyes faded back to green.

"Not sure just yet, let me sleep on it and we'll finish talking in the morning?" Lexi said as she moved to get up only to have Derek pull her down with him. "You want me to stay?"

"Yeah, if you don't mind?" Derek questioned, Lexi waited a second before Derek's fingers felt their way back into her grip.

"Alright," Lexi yawned again before the two of them found themselves drifting off to sleep. Derek's grip tightening on Lexi as they did so as he felt another nightmare coming on. Lexi felt his nightmare start and decided to take a look inside while they slept. 'Shh Derek, it's okay, remember this happened a long time ago,' Lexi said as her subconscious took hold of Derek's hand and he looked at her.

'We weren't home...we couldn't stop it,' Derek didn't question why Lexi was suddenly in his nightmare he just answered her as though she was always there.