Piranesi’s house is no ordinary building: its rooms are infinite, its corridors endless, its walls are lined with thousands upon thousands of statues, each one different from all the others. Within the labyrinth of halls an ocean is imprisoned; waves thunder up staircases, rooms are flooded in an instant. But Piranesi is not afraid; he understands the tides as he understands the patter of the labyrinth itself. He lives to explore the house.

There is one other person in the house, a man called The Other, who visits Piranesi twice a week and asks for help with research into A Great and Secret Knowledge. But as Piranesi explores, evidence emerges of another person, and a terrible truth begins to unravel, revealing a world beyond the one Piranesi has always known.

In 1977, Claire Lake, Oregon, was shaken by the Lady Killer Murders: Two men, seemingly randomly, were murdered with the same gun, with strange notes left behind. Beth Greer was the perfect suspect - a rich, eccentric twenty-three-year-old woman, seen fleeing one of the crime scenes. But she was acquitted, and she retreated to the isolation of her mansion.

Oregon, 2017. Shea Collins is a receptionist, but by night, she runs a true-crime website, the Book of Cold Cases - a passion fueled by the attempted abduction she escaped as a child. When she meets Beth by chance, Shea asks her for an interview. To Shea’s surprise, Beth says yes.

Upstate New York, 1982. Viv Delaney wants to move to New York City, and to help pay for it she takes a job as the night clerk at the Sun Down Motel in Fell, New York. But something isn’t right at the motel, something haunting and scary.