"ISAAC, take your hands off my sister!" Isaac Lahey x Reader

Surprise To See Another McCall

Maybe things had never 'clicked' in Isaac's head before until now. Sam, the girl who he had just now noticed in High School, was Scott McCalls twin sister. I mean sure, he never really payed much attention in class and he had more troubling matters to deal with at his house, but one would think that he'd notice a fellow classmate! Of course, we have to give Samantha some credit too, for she had grown quite more beautiful over the summer. Someone was bound to see her with admiring eyes.
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Scott was surprised to hear a knock on his bedroom door late at night. He was halfway expecting for it to be his mom or his sister. 
"Come in mom." Scott said, not turning around to even look at who was standing in the doorway.
"I was wondering if I could ask you a favor." Isaac said, making a confused Scott turn around.
"W-why are you..?" Scott uttered.
"Derek kicked me out. Said he didn't want me, and he threw a bottle of whiskey at me." Isaac admitted solemnly while looking down at the ground with sad eyes. He had lost his parental figure. Again.
"Can I stay here for the night? I'll be gone by the morning I just need somewhere to sleep until I can find somewhere..."
"Yeah, Isaac. But you can stay as long as you'd like." Scott replied.
"A-are you sure? I don't want to intrude." Isaac asked.
"Yeah," Scott sighed. "I'm sure."
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Scott showed Isaac to the guest bedroom and Isaac put what little belongings he had in the closet. He was exhausted; physically and emotionally, and he concluded he needed to just go to sleep and stop thinking about the nights events. He collapsed onto the bed and quickly fell asleep.
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At around 2 a.m. Isaac awoke thrashing and sweating. He had been having bad dreams about his upbringing ever since he was about twelve, but recently his dreaming had become more severe after his father died. Yes, he was a bad man, but he didn't always used to be like that.
Isaac trudged downstairs in search for a glass of water to quench his nightmare thirst, completely unaware of the McCall counterpart leaning against the counter-top, munching away on her cherry poptart. Odd, yes, but pop tarts simply hit different in late hours of the night.
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*Sam's p.o.v.*
I heard the creaking of the stairs, as if someone was coming down them. I honed in on my werewolf hearing ability's to see who it was. The person's footsteps trudged like a man, immediately marking off the possibility of it being mom. To double check this I listened and heard her slow, even breaths coming from her bedroom, fast asleep. Therefore, with mom out the picture, it had to either have been Scott, or an intruder. I listened carefully, noticing the mystery persons walking strides and pattern of footsteps as they fell onto the floor. Quickly realizing that they were not Scott's footsteps, I grabbed the nearest kitchen knife off the counter holder, and launched it at the doorway where the intruder was set to be placed at.
Isaac, being the werewolf he is, sensed an object flying at him and immediately ducked in the doorway.

"What the fu-" Isaac said upon seeing a knife wedged into the wall where he was previously standing in front of seconds before.
Samantha, realizing he was Scotts friend due to seeing him around school before, said,
"LAHEY! Wtf! I about killed you!"
Isaac, with a pricelessly confused face, replied back,
"Well sorry! You just gave me a heart attack! I came down here to get a glass of water. I didn't order knives being thrown at me too! I'm going to have PTSD from the amount of shit I've had thrown at me the past few months."
"Oh, yeah sorry. It wasn't my intention to hurt you. I thought you were an intruder. I was going to kill the intruder. If I had known it was you I wouldn't have sent a knife in that direction."
"So what are you doing here? Are you friends with Scott too?" Isaac asked.
"Pfft. Friend is far fetched. Try his sister."
"Sis-Sister?!?"
"Yes, sister."
"I didn't know Scott had a sister."
Sam sighs.
"Stiles was right. You really do have the intelligence of an Afghan Hound."
Isaac dramatically gasped, slightly offended, and replied back,
"And Derek was right for saying you have a unwanted opinion about everything."
"It's' not an opinion if It's a fact."
"Facts require evidence."
"I can get witnesses."
Isaac roles his eyes in defeat bc he realized it was pointless in arguing with Sam bc he can't win.
"So Lahey, wanna remind me as to why you are standing in my kitchen at precisely 2:10 a.m.?"
"Derek kicked me out of the loft and said he didn't want me no more and that I was basically a burden before throwing a bottle of liquor on the wall above my head. Scott let me stay in the guest bedroom." Isaac explained dejectedly.
"Sad story Lahey. Sorry to hear that."
"You know my first name is Isaac, right?"
"Yeahhhh, but I think I'll call you Lahey," Sam said, patted his shoulder and left the kitchen with her poptart in the other hand.
"Sweet dreams wolf boy!" Sam called from the stairs.

'Well this should be interesting.' Isaac thought as he got himself a glass of water and went back to bed in a dreamless sleep.