Will, just being a 12 year-old boy, rides his bike through the woods passing by a laboratory. He sees something strange in front of him which causes him to panic and fall down a hill and crash. He abandons his bike and runs back home where he finds no one. He tries to call his parents but he only hears a whispering voice as someone tries to open the door. Will gets scared and runs to his shed in the backyard where he sees the same strange thing he saw when he crashed that vanishes him into thin air.
The next morning Will’s mom finds that he has mysteriously disappeared. The whole town goes looking for him and begins to uncover secrets of the government laboratory. They discover there are portals to another world, frightening monsters, and a strange little girl named eleven. Eleven manages to escape from the laboratory. She ends up finding Mike Wheeler who is one of Will’s best friends. Eleven then uses her supernatural abilities to help locate Will. When they find him will he still be alive? And will they be able to rescue him?