On a quiet, rural Lancashire army base, soldiers are being mauled to death in the surrounding woodland, a mystery that unsettles everyone and fuels rumors of a wild animal at large. The danger, however, feels closer to home for two sisters who live nearby. Joyce Ballantyne, Flora Robson, and Ellie Ballantyne, Beryl Reid, share a house that overlooks the base and keeps a watchful eye on the unfolding fear around them.
As fear deepens, the sisters grow convinced that the killer is not a creature but their own younger brother, Steven Ballantyne, Dafydd Havard. Steven has been kept hidden in their cellar for nearly thirty years, a secret that weighs heavily on the family’s past. The sisters uncover a tunnel that Steven has dug, allowing him to slip in and out at will, which confirms their worst fears. They also discover the body of a soldier, and in a desperate attempt to protect themselves and the others, they seal the tunnel from the inside. In the chaos of the discovery, Joyce suffers a bad fall and is pushed into bed, while Ellie must complete the grim task alone, burying the victim close to the house.
With Joyce incapacitated, Nurse Sutherland, Tessa Wyatt, arrives to care for her, bringing a fragile routine of routine watchfulness and concern. Ellie comes to a stark realization: she cannot manage everything by herself and decides to involve the army and the police. She reveals a long and troubling history: Steven is their younger brother, born after their soldier father returned from the First World War. Their father’s war experiences left him shell-shocked and violently unstable, a trauma that cast a shadow over the family. After their parents died, Joyce, determined to prevent Steven from ending up like his father, resolved to keep him out of military service at the outbreak of the Second World War. To protect him, the sisters had drugged Steven and confined him in the cellar, later adding sleeping pills to his water to keep him subdued. Over the years, that confinement and abuse have warped Steven, breeding a deep hatred of uniformed soldiers and turning him into something savage.
Steven returns to the house, lunging at Joyce while wearing their father’s army overcoat and cap, a moment that underscores the terrible history of the family. He is fatally shot by one of the soldiers, a tragedy born of fear and years of coercion. In the immediate aftermath, Ellie realizes that the attack was not meant for Joyce alone; it was directed at a framed bedside photograph of their father in uniform, a symbol of the family’s haunted past that finally reveals the true emptiness of the violence that has pursued them.
