Five kids are on a sleepover in a restored wilderness project in Ireland. With them, three teachers and one Ranger: Lisa. She is 26, longing to leave her job, out of her depth and soon to find herself mired in a nightmare.

Strange things have been happening at Lough Carrow, a vast rewilding project on the site of a former commercial peat-bog. Livestock mutilations. Rumours, myths from the neighbouring villages. Strange, unidentifiable tracks. On the trek in to the sleepover site they sight animals that have not yet been introduced to the park - wolves, wolverines, things older. Things thought long extinct.

As they near the centre of the wilding a boy realises he's forgotten his meds. A teacher volunteers to take him back to the visitor centre. Sure, what could go wrong?