Halloween Glass at Blackwater

Grew up in the archive wing of Blackwater House, on the River Nore in County Kilkenny, where her father Seán still reads the names off other people's papers aloud, like a prayer. When she was eight, a voice called her from the attic door: "Mammy, come up." She has not spoken of it since, and she has made a career of walking into other people's haunted rooms with a camera, a black notebook and her husband Cian, who measures everything twice.

Their casebook takes them from a farmhouse in Donegal to a Dublin housing estate, a hospital ward in Galway and a rented house in the Wicklow hills. Each family is struggling with money and fear, and each is sleeping badly. A voice calls the children by name.

A woman is seen in glass. Knocking starts at the same hour every night. The cases look unrelated until Maeve notices the small, strangely identical pewter charm that a dealer gave to the children of each house, and then the catalogue number on the black-foxed oval mirror that went missing from her father's archive in 1991.