In rural England, slowly emerging from the sorrow of World War I, the peace of a small Surrey village is shattered by a murderous attack on a household that leaves five butchered bodies and no explanation for the killings. Sent by Scotland Yard to investigate is Inspector John Madden, a grave and good man who bears the emotional and physical scars from his own harrowing war experiences and from the tragic loss of his wife and child. The local police dismiss the slaughter as a robbery gone awry, but Madden and his chief inspctor detect the signs of a madman at work. With the help of Dr. Helen Blackwell, who introduces Madden to the latest developments in criminal psychology and who opens his heart again to the possibility of love, Madden sets out to identify and capture the killer, even as the murderer sets his sights on his next innocent victims.