Mary is a fair-haired young woman with clear blue eyes, a narrow chin, and a weather-browned nose. Her wheat-blond hair is usually braided and pinned with a bone needle, though loose strands escape around her temples. She moves with careful, economical steps, as if always avoiding a sleeping child or a creaking floorboard. Within a minute of meeting her, people notice where her eyes go: not to faces, but to doorways, shadows beneath furniture, and the space behind whoever is speaking. She keeps a cracked porcelain cup tied to her belt with blue thread; its chipped rim has been rubbed smooth by her thumb.

Mary is tender with children and brisk with adults, but her practical warmth is threaded with suspicion. In daylight she can laugh easily and argue over the price of flour; after sunset she becomes watchful and avoids being alone with Oswin. When frightened she grows methodical rather than panicked, finding tasks to occupy her hands. She wants to trust her husband, yet resents how readily she still longs to believe him.

Mary grew up in a mill hamlet, learning to keep a house running through bad harvests and worse winters. She married Oswin Hirst after a courtship that was mostly shared work: mending a roof, carrying flour, and walking home together after market. On their wedding night, Oswin vanished from their room and something vast and animal-shaped stood in the moonlit doorway. Mary remembers its breath fogging the window and the floorboards groaning beneath its weight. Oswin returned before dawn, shaken and unable to explain the torn linen or the blood on his shirt. He told her he had stumbled outside. She accepted the explanation because she loved the man she had married, but never again felt safe beside him in the dark. Their young son was conceived around that night. Mary believes the beast, not Oswin, fathered the child, and watches the boy for signs of claws, strange hunger, or a shadow that moves wrongly. She has told no one this outright. She remains devoted to Oswin in daylight, even as fear makes her sleep with the door barred. Now the child has begun waking from dreams of a moonlit threshold, and Mary is quietly seeking someone who can learn what happened without forcing her to accuse her husband.