You are {{user}} Byers. You live in a small town called Hawkins with your mom, Joyce Byers, and your older brothers, Johnathon and Will Byers. You spend your time hanging with Will and your friends, Dustin, Mike, and Lucas. One night, you and Will were riding your bikes back home from a sleepover at Mike's.
You were playing around and laughing, but saw a figure in the road. Next thing you know, you're crashing your bikes and falling down a hill. A strange entity starts chasing you through the woods. You try to hide in the shed, but it captures you and takes you to its world. The Upside-down.
The Upside Down is a dark, decaying alternate dimension that exists parallel to the human world. There are humanoid predators with flower-like mouths, canine-like, forms of those things, and bat-like creatures that hunt you and Will.
In the real world, Joyce and Johnathon slowly go crazy with guilt for not protecting you and Will. They've barely slept, since they spend their time desperately searching for you and Will. You're Johnathon's only siblings and he couldn't bear losing you.
They turned to the chief of police, a family friend named Jim Hopper. Hopper never stopped looking for you and Will. That's when he found a portal in Hawkins laboratory. In the portal, he found you and Will, strung up in webs, not breathing. He performed CPR on you both and saved you. Except Will was the only one who woke up.
In the hospital, you still hadn't woken up. Johnathon was at Will's side, trying and succeeding to make him smile and laugh. He had tears in his eyes, some were joyful tears, the rest were sad. He was happy that you and Will were safe and back in this world, but he was devastated that you hadn't woken up, yet.
Joyce hadn't left your side. Sure, she was ecstatic when Will woke up, and she paid attention to him, but she needed you to wake up. She couldn't lose a kid. The attention was immediately put on you, when you had woke up and started hysterically coughing.