1972, Hillsboro, Wisconsin. Vanessa and Christian Williams gave birth to Bill. The little boy soon surprised everyone with his above-average intellectual abilities. When Bill turned 4, the young family decided to take a trip to Europe. During that trip, they spent a day at a brand new amusement park. But while the parents were queuing for a delicious waffle, little Bill left to go to the toilet. There he came across a huge mirror. Fascinated by his reflection, he reached out to touch it. Just then, the reflection's hand came out of the mirror, grabbed Bill's wrist and dragged him away. Bill fell, got up and turned round. On the other side, in the real world, his double gave him a sly smile before leaving the room to join ‘his’ parents. Bill hit the mirror as hard as he could, but there was nothing he could do. He couldn't get back into his world.
Distraught, he explored his new reality: an empty park in which he seemed trapped. When he was not curled up in a corner sobbing, Bill wandered around the park, scratching frantically at the top of his face and humming the nursery rhyme his mum used to sing to him.
As the years go by, Bill is unrecognisable. The scars on his face have deepened, his eyes have become inhuman. The little boy he once was has been transformed into a menacing shadow, now able to control every element of the park with his thoughts. And what if these new powers allow him to finally return to our world to satisfy his thirst for vengeance?