A/n
Imma write the timeline so you don't get confused ( It doesn't follow Tw original timeline )

Freshman year:
September--November Tw season 1
November--February Tw season 2
February--April Tw season 3a
April--June Tw season 3b
June: Stiles and Allison gets kidnapped

Sophomore year:
Malia joins the pack, Kira, Jackson and Ethan don't leave Beacon Hills. Everyone (- the Sheriff ) gives up on finding Stiles.

Junior year
Season 4 ( without Stiles ofc )

Senior year:
September: Stiles/Thomas and Allison/Teresa come back
Half September: the two of them are out of the pack
November: the Glanders/Scorchers come to Beacon Hills

( I wrote the school timeline as it is in my country, basically we go to school from September to the first week of June, then we have 3 month summer break until the next school year, hope you understand lol )   

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*Flashback June of Freshman year*

Stiles pov.:

I took a deep breath to try to calm down, my hands were shaking, my hair was wet from the rain. The shirt was still stained with blood, like my sweatshirt. I was free, I was finally free from nogitsune, but at what price?
Aiden is dead and now Allison is dying too. We are in the hospital, I have heard the doctors saying that maybe she will not make it. I can't lose her, not her, since we met Allison has been a sister to me, I can't imagine my life without her, she has always been beside me, unlike Scott...

A nurse arrives, tells us that she has a 50% chance of surviving, now she is in a coma but she can hear us. After the nurse leaves, Scott gets up and orders me to get up, I do and he slaps me. Nobody speaks, nobody breathes.

"Are you happy now?! Allison is dying and it's your fault!!" I heard him scream
"I- I -..."
"I don't wanna se your face here, get out!!"
"Scott ..."
"I SAID GET OUT!!"
"YOU CAN'T DO THIS! YOU KNOW ITS NOT MY FAULT, IT WAS THE NOGITSUNE!" I snapped, but one side of me know I'm lying, its all my fault...

Scott pushes me to the ground, I almost bang my head, in tears I decide that it is useless to talk to him, I slowly get up and run away from the hospital, ignoring the screams that shout my name. I run and run like I've never done before, only now do I realize how fast I am.
I stop to take a breath, I'm in the preserve, I feel someone hit me in the back of the head, it hurts, my muscles are like glued to the floor, the view becomes increasingly blurred.
"Good luck Thomas, subject A2" I hear a man say.

That's the last thing I hear.

Allison pov.:

I'm lying on this stupid hospital bed, I've heard Scott and Stiles arguing; I wanted to get up, yell at Scott that it wasn't Stiles' fault. I wanted to defend my best friend, my brother. But I can't, because I'm in a coma because of that stupid nogitsune.
I swear as soon as I wake up from my coma, I'll kill Scott. At one point I hear a voice of a woman, a nurse, speaking to the pack.

"I'm sorry for your loss, she didn't make it..."
Wait...WHAT ?! I AM HERE I AM NOT DEAD.
I panic, the machinery is not broken, I hear the classic beep beep.
"Well, we can proceed, good luck Teresa, subject A1...She's the last one EVER"
I feel a needle in my arm, and then I pass out.

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Lmao this is really bad 😫🤚🏻

Btw Allison/Teresa did betray the Glanders/Scorchers, but everyone forgave her because she was manipulated by Janson; Newt got the cure in time, Brenda got just before Stiles/Thomas was pulling the trigger.
Teresa didn't die.

See ya 👀✨