Their dark legacy dates from before the dawn of recorded human history. Their reach echoes through the ages, an evil too terrible to comprehend and a strength to rival the greatest angels of heaven and the foulest of the fallen in hell. They are Legion, a horde of countless demons acting as one, united in mind and purpose. When Scott Macklin's father dies, Scott begins to uncover the secrets behind his father's involvement with a mysterious group known as The Shadowed Ones. With a conspiracy of dark forces pressing in from every side, Scott finds that he is not alone in opposing Legion. He is joined by Douglas Prichard, a dedicated military commander; Father William Los Cruzado, a priest with a shady past; and Dr. Rachel Walters, a skilled hostage negotiator. Together they must face this force of darkness known as Legion. With little but their faith to guide them, they must hold back a rising tide of evil that threatens to consume the souls of all mankind, without falling prey to their own human failings.