Rin, a war orphan and slave, discovers she possesses shamanic powers that could save her people or destroy them. Against all odds, Rin aces the Keju, the empire-wide test to find the most talented youth, and is admitted to the most elite military academy in Nikan. There, she struggles to keep up with the privileged cadets and faces prejudice due to her dark skin and peasant background. As war with the northern Federation looms, Rin must master her volatile powers, confront the brutal realities of combat, and decide whether to embrace the destructive potential of the gods or find a different path.

The Poppy War has been widely praised for its ambitious scope and unflinching depiction of warfare. Critics often highlight its dark themes, intricate world-building, and the compelling, morally complex protagonist. The novel is frequently lauded for its unique blend of fantasy elements with historical realism, drawing comparisons to military epics. Readers generally respond to its intensity and the raw portrayal of a young woman's struggle for power and survival in a brutal world.