Description
Soldiers stationed at a rural army base are being mauled to death in the surrounding woodland. The authorities suspect a wild cat, but sisters Joyce and Ellie Ballantyne (Flora Robson and Beryl Reid), who live in a house nearby, fear that the soldiers are actually being murdered by their brother Steven (Dafydd Havard), who has been locked in their cellar for nearly 30 years.
Joyce and Ellie discover that Steven has dug a tunnel out of the cellar, allowing him to come and go as he pleases. They also find the body of one of the soldiers. As they fill in the tunnel, Joyce suffers a fall, forcing Ellie to complete the task alone. Ellie then buries Steven's victim near the house.
With Joyce now bedridden, Ellie realises that she cannot cope on her own and calls in the army and police. She tells them that Steven is her and Joyce's younger brother, born after their soldier father's return from the First World War. She adds that their father had been left shell-shocked by his experiences and was violent towards Steven. After their parents died, Joyce, not wanting Steven to end up like his father, resolved to prevent him from being called up at the start of the Second World War. To this end, she and Ellie drugged Steven and placed him in the cellar, thereafter lacing his water supply with sleeping pills to keep him under control. After being physically abused by his soldier father, then incarcerated for three decades by his sisters, Steven has developed a hatred of uniformed army men and regressed to the level of a savage.
Steven re-enters the house and lunges at Joyce, who is wearing their father's army overcoat and cap. He is fatally shot by one of the soldiers. Ellie realises that Steven did not mean to attack Joyce, but a framed bedside photograph of their father in uniform.
