Sophia is 13 and her brothers take her on a hunt involving a witch who puts a de aging spell on people, Dean then has his siblings separate to cover more ground. As luck would have it Sophia found the witch she then begins fighting with the witch but she doesn't hear the witch saying the spell then out of nowhere Sophia falls unconscious on the floor then Dean and Sam come in the room.
"Sam check on Soph i got this bitch". Dean said to his brother.
"Bring it on". The witch said.
Sam then picks his sister up effortlessly because she is almost light as a feather. Sam then tries everything to wake his sister up but can't just then Dean is finished with the witch and neither brother knows Sophia has been cursed with the de aging spell. Dean then picks up his unconscious sister and brings her out to the car laying her in the back seat covering her up with one of his jackets.
"Dean do you think she put that spell on Soph?" Sam asked.
"I don't know we'll check her when she wakes up". Dean replied.
They then drive back to the bunker and puts Sophia to sleep in her room while the brothers have a beer in the living room then about 2:30 they head up to bed. While in Sophia's room she starts to change from being a teenager to a 4 year old toddler.
The next morning
Sophia is up early but since she is now only four years old she doesn't know where she is her bottom lip starts to quiver and she starts crying loudly. Dean and Sam then hears crying coming from their sister's room so they bust in with their handguns and nothing is there then Sam looks over to his sister's bed in shock to see his 13 year old sister turned into a small helpless four year old.
"Uh Dean look". Sam whispered to his brother.
Dean then looks to his sister's bed and sees exactly what Sam saw his 13 year old sister is now a toddler. He then puts his gun away and goes to his sister's bed sitting down on it.
"Soph?" Dean asked wanting to be sure.
Sophia then looked up through her bleary eyes and saw Dean sitting on the bed.
"Dean". Sophia cried throwing her arms around his neck.
"Hey. Hey it's alright Soph. It's alright me and Sammy are here". Dean soothed her.
"Where are we De?" Sophia asked.
Dean then looked at his brother and wondered why his sister doesn't remember anything but them.
"Were at the bunker Soph. We live here remember". Dean said.
"I don't remember". Sophia said.
"It's alright Soph". Dean said.
"I'm hungree". Sophia said.
"Then how about we go get some food in your little tummy then huh". Dean said tickling her.
"Stop De. Tickles". Sophia said laughing.
Dean then stops ticking her then looks down and sees she's in her old clothes.
"Yeah i think we need to go shopping Dean". Sam said.
"Can we get toys to?" Sophia asked excitedly.
"Yeah we can get toys too". Dean said.
Sam looks at his brother and sees how happy he is but they also know they have to find a way to change back their sister and if they can't she will be forced to relive her life but with Dean and Sam raising her.