Faust is a reincarnated Japanese man who wakes up in a medieval fantasy realm where women outnumber men nine to one. In this world, chastity norms and gender roles are completely reversed, placing women in positions of political and military power while men are often treated as second-class citizens or decorative consorts. Faust, however, is an anomaly. Raised as a frontier lord in the impoverished Polidoro fief after being born to a noble mother who genuinely loved his father, he is the world's only male knight. Standing over six and a half feet tall and wielding a massive enchanted greatsword, his battlefield prowess has earned him the moniker the Knight of Wrath. The truth behind his perpetually red-faced, furious expression is far less intimidating: he wears a painful steel chastity belt to conceal his frequent and very visible attraction to the many beautiful women who surround him.

Clinging to his modern Japanese values, Faust struggles to navigate a court where the queen wears barely-there attire and a buxom duchess uses diplomacy as a pretext for harassment. To support his poor fief, he enters a mutually beneficial arrangement with Princess Valiele, the scrawny and disfavored younger daughter of the queen. He advises her on matters of state, and she provides him with funds and food. When Queen Liesenlotte orders Valiele on her first military campaign to suppress a bandit threat near the border with the hostile kingdom of Villendorf, she assigns Faust as the princesss mentor. The queen threatens to reassign Faust to the service of Valieles politically powerful older sister if the mission fails, raising the stakes considerably. Faust and Valiele set out with a small force consisting of his twenty armswomen and her fifteen inexperienced knights. Among Valieles retainers is Zabine, a knight who desperately wants to not die a virgin and sets her sights on seducing Faust. Upon reaching a remote village, the group discovers the situation is far worse than reported, encountering a tragedy that will test Fausts skill, courage, and honor like never before.

During the campaign, Faust faces Caroline von Bosel, a formidable rebel whose failed coup attempt forced her into banditry. Faust ultimately kills Caroline in single combat, leaving behind a nine-year-old daughter named Martina. When Queen Liesenlotte orders Faust to execute the child as a traitors spawn, a punishment he finds abhorrent due to his modern ethics, he refuses and instead invokes a royal boon to claim Martina as his squire. After the campaign, Faust returns to his quiet frontier fief only to be summoned back to the capital for a delicate diplomatic mission. Queen Liesenlotte tasks him with acting as an envoy to negotiate peace with the neighboring kingdom of Villendorf, a mission whose success depends entirely on his ability to charm Queen Catalina, a ruler famous for her ruthlessly cold heart.