In 1925, London solicitor Arthur Kidd travels to the coastal market town of Crythin Gifford on England's east coast to attend the funeral and settle the estate of their client Alice Drablow, a reclusive widow. On arrival, he meets Sam Toovey, a local landowner, and finds the townspeople reluctant to talk about Drablow's home, Eel Marsh House.
At the funeral, accompanied by local solicitor Pepperell, Kidd notices an apparent mourner, a Woman in Black, but Pepperell grows frightened when Kidd mentions her. Later, Kidd saves the life of a Romani child when logs break free from a lumber truck.
A local coachman takes Kidd to Eel Marsh House, which can only be reached by a tidal causeway that appears at low tide. He shows him how to start the generator that powers the house's electric lighting. Left alone, Kidd explores the family graveyard and sees the mysterious Woman in Black, terrifying him. In the study, he finds two death certificates and photographs of a young woman resembling her, and he listens to disturbing wax cylinders recorded by Mrs. Drablow. A short time later, the coachman arrives to take him back to town.
Toovey tells him not to return to the house, but Kidd insists he will not be afraid this time. Toovey loans Kidd his dog Spider. On his return, Kidd hears the sound of a bouncing ball emanating from upstairs. Spider starts barking and leads Kidd to a locked door. Kidd fetches an axe to break the door, only to find it opened by itself. Inside is a pristinely-kept nursery. Kidd hears a child’s greeting and opens his hand to find a lead soldier. The generator runs down, and he rushes outside to restart it.
Outside, Spider answers a whistle and runs away into the night. Kidd again hears the echoing sounds of the drowning horse, woman, and child in the marsh. Frightened almost to madness, he takes refuge in the house and records his fears onto the wax cylinders.
From Mrs. Drablow's papers, Kidd learns that Mrs. Drablow's sister Jennet Goss had a child out of wedlock. The Drablows adopted the boy to save face, insisting he should never know Jennet was his mother. Jennet kidnapped her son and tried to escape via the causeway, but the pony and trap sank in the marshes, killing all aboard.
Toovey arrives at Eel Marsh House, brought by Spider. He reveals that seeing the Woman in Black presages the death of a child. Kidd shows Toovey the recordings and the nursery. However, the room is mysteriously a mess, with all the toys smashed. Shocked, Kidd collapses.
Kidd wakes in the town inn to the sound of a child's laughter and finds the lead soldier yet again in his hand. After asking what the child wants, the Woman in Black appears and shrieks in his face, terrifying him into unconsciousness.
Kidd falls ill for a few days, and the Tooveys look after him. When he recovers, he returns to London and his family. Back in the office, his two assistants say that there was a customer waiting for him, a woman dressed as a widow in black. Kidd searches Mrs. Drablow's papers for the toy soldier, and when he does not find it, he burns the papers and the box, and ends up burning half his office as well. His boss fires him.
Later, Arthur and his family are boating on a lake when Arthur sees the Woman in Black standing on the surface of the water. A tree falls on their boat, crushing and drowning them all.
