"Martyr" vividly portrays the life of Dmitri Ivanovich Kuznetsov, from his humble beginnings to his final moments in a cold, lonely grave. However, his journey doesn't end there. To the astonishment of an old priest, Dmitri's afterlife doesn't lead to heaven and God but to a new world—the Gu world, bathed in the light of a new day. Here, Dmitri's purpose transcends peace; he becomes the Sword of Christ, wielding his faith against the shadows that lurk in this unfamiliar realm.

In this Gu world, where darkness reigns, Dmitri's arrival heralds a glimmer of hope. As the Sword of Christ, he is determined to bring God's light to this realm, where darkness threatens to engulf all. With unwavering faith and resolve, Dmitri confronts the challenges and dangers that loom, using his faith as a beacon of hope amidst the shadows. As he navigates this mysterious world, he not only grapples with his newfound role but also serves as a symbol of divine grace, spreading God's light to dispel the darkness that threatens to consume the Gu world.