January 1937. Jack Miller has just about run out of options. His shoes have worn through, he can't afford to heat his rented room in Tooting, and he longs to use his training as an specialist wireless operator instead of working in his dead-end job. When he is given the chance to join an arctic expedition, as communications expert, by a group of elite Oxbridge graduates, he brushes off his apprehensions and convinces himself to join them.

Renowned academic Dr Sparling seeks help with his project on a remote Irish village. Historical researchers Ben and Chloe are thrilled to be chosen—until they arrive. The village is isolated and forgotten. There is no record of its history, its stories. There is no friendliness from the locals, only wary looks and whispers. The villagers lock down their homes at sundown. A nameless fear stalks the streets. Nobody will talk—nobody except one little girl. Her story strikes dread into the hearts of the newcomers. Three times you see him. Each night he comes closer.

This forest isn't charted on any map. Every car breaks down at its treeline. Mina's is no different. Left stranded, she is forced into the dark woodland only to find a woman shouting, urging Mina to run to a concrete bunker. As the door slams behind her, the building is besieged by screams. Mina finds herself in a room with a wall of glass, and an electric light that activates at nightfall, when the watchers come above ground. These creatures emerge to observe their captive humans and terrible things happen to anyone who doesn't reach the bunker in time. 

Struggling with money, raising a child alone, and fleeing a volatile ex, Jess McMachen accepts a job caring for an elderly patient. Flo Gardner–a disturbed shut-in and invalid. But if Jess can hold this job down, she and her daughter, Izzy, can begin a new life. Flo's vast home, Nerthus House, may resemble a stately vicarage in an idyllic village, but the labyrinthine interior is a dark, cluttered warren filled with pagan artefacts.

In a lonely village in the Peak District, during the onset of a once-in-a-lifetime snow storm, Constable Ellie Cheetham finds a body. The man, a local ne'er-do-well, appears to have died in a tragic accident: he drank too much and froze to death. But the facts don't add up: the dead man is clutching a knife in one hand, and there's evidence he was hiding from someone. Stranger still, an odd mark has been drawn onto a stone beside his body.