A young boy named Peetah Cuckole (Iain Armitage) is exploring the woods when he finds a glowing green amulet embedded into the trees. He grabs the amulet and welds it into a necklace, he gives the necklace to his crush Sarah (Elise Cumayayay). The next day he notices something off about Sarah.

Peetah notices Sarah’s eyes are glowing green. She has been possessed by a dark shadow spirit! Sarah is violent and won’t let anyone touch her, but Peetah somehow manages get the amulet off of Sarah. The dark shadow spirit is sucked out of Sarah and appears to be going back into the amulet, but then the dark shadow spirit flys off into the sky unleashing terror on their town.

A green sky and fog covers the town. The radio station and mayor release statements and warnings to stay indoors. Peetah sees his neighbor go into the fog, only to come out possessed by the dark shadow spirit. Worried, he and his family lock all their doors and windows and ration their food.

A horrible storm with green lightning rolls through Cumsdale. The Cuckole family begins to discuss what is going on and how to handle it. Meanwhile, the town mayor gets struck by the lightning and was transported into the shadow realm where he gets tortured by otherworldly beings.

Bethany Cuckole finds an old puzzle box in her basement. She notices the amulet fits perfectly inside a divot in the box. It lets out an electric shock that brings her into the shadow realm. Bethany sees the mayor being tortured by the creatures. Bethany is able to go unnoticed and hide, and so she begins to make a plan to escape.

After wind from the storm causes a tree to fall on their house, the fog from outside seeps in and infects Peetah’s parents. Peetah is able to run to his bedroom in time and lock the door to stay safe from his parents. He puts a mask over his face and crawls out his window to the outside, where he goes looking for his friends.

The creatures see Peetah has left his house and is out in the fog, so they all open a portal to the real world and go after him. Now that the creatures are gone, Bethany and the mayor are able to escape the shadow realm and return to the real world, but not before taking a book from inside the creatures lair.

The creatures find Peetah and capture his soul inside a green bead and take it back to the shadow realm. Bethany and the mayor return to town hall and begin studying the book for answers on how to break the curse. And they are able to round up the townspeople and unpossess them.

Bethany, the mayor, and the townspeople all begin throwing out ideas on how to break the curse from their town, but to do it they discover they will need Peetah. They assemble teams to enter the shadow realm and find Peetah and defeat the creatures. And then the teams solve the puzzle box and enter the shadow realm.

One team distracts the creatures while other other looks for Peetahs bead and shatters it, unleashing his soul back into his body in the real world. In both dimensions, the teams and the townspeople deploy a gateway between worlds to return the teams back to real world and anchor the creatures to their dimension.