Oli, an overworked office worker, dies suddenly and transmigrates into a novel as the illegitimate daughter of a duke's household, where she is constantly mistreated. At the brink of despair, she makes desperate wishes and unexpectedly awakens her ancient bloodline, transforming into a palm-sized, black-furred magical creature resembling a little lump of coal. Just as Sien, the God of War from the original novel, is about to meet his destined doom, the tiny coal ball rushes to the battlefield. Using her ability to devour catastrophic poisons, she stubbornly protects him, unaware that every time she reverses fate, her own existence gradually fades away.