The central conflict of the novel revolves around the discovery of a mysterious alien race known as the Usurpers. These beings possess advanced technology and a hostile attitude toward humanity seeking to conquer and subjugate human colonies throughout the galaxy. As the Usurpers launch their campaign of conquest humanity faces a desperate struggle for survival. The novel follows a diverse cast of characters including military leaders scientists and ordinary citizens as they band together to resist the alien invaders and defend their way of life.