In the wink of an eye, as quick as a flea,
The Devil he jumped from me to thee.
And only when the Devil had gone,
Did I know that he and I'd been one . . .

Every autumn, John Pentecost returns to the farm where he grew up, to help gather the sheep down from the moors for the winter. Very little changes in the Endlands, but this year, his grandfather--the Gaffer--has died and John's new wife, Katherine, is accompanying him for the first time.

Each year, the Gaffer would redraw the boundary lines of the village, with pen and paper but also through the remembrance of tales and timeless communal rituals, which keep the sheep safe from the Devil. But as the farmers of the Endlands bury the Gaffer and prepare to gather the sheep, they begin to wonder whether they've let the Devil in after all.