Four young offenders and their workers spend a weekend in the remote Yorkshire village of Mortlake, which prides on keeping itself to itself. A minor incident with locals rapidly escalates into a blood-soaked, deliriously warped nightmare.

Two siblings begin to develop special talents after they find a mysterious box of toys, and soon their parents and even their teacher are drawn into a strange new world – and find a task ahead of them that is far more important than any of them could imagine.