In an apocalyptic world ravaged by monsters and frequent disasters, every ounce of power comes at a price. A young man codenamed Long possesses a god-tier innate ability called Ruler, which allows him to exchange his lifespan for power. He has deliberately kept this ability sealed away. But when the red moon hangs high in the sky, crimson fog engulfs the city, and deadly disasters descend, humanity is pushed to the brink of despair. Armed with a Tang dynasty saber, he steps forward to fight the calamities, wagering his own lifespan. With the power to rewrite the world's rules, he must make one difficult choice after another, balancing his remaining years, the disasters, and human nature as one ultimate crisis after another unfolds.