Cain: A Mystery presents a unique retelling of the biblical story of Cain and Abel from the perspective of Cain himself. Influenced by Milton's Paradise Lost, Byron's Cain is a defiant and inquisitive character grappling with the mortality and punishment imposed on humanity. Guided by Lucifer through the vastness of space, Cain gains an expanded understanding of Earth's violent history and the true nature of death. Returning from his cosmic journey, Cain's comprehension of his own mortality leads him to commit the infamous act of fratricide, fulfilling the tragic destiny depicted in the biblical narrative.