A humble downtown chef named Kengo, a man in his forties running a modest Western-style restaurant, dies after a violent altercation with a customer and awakens in a fantasy world as a beautiful young princess. He is stranded in the wilderness alongside Auguste, a devoted knight who was in love with the princess before the soul swap. With no way back and only dangerous, unfamiliar monsters and plants available as ingredients, Kengo relies on his professional cooking instincts to survive. He begins turning creatures such as giant snakes, toxic tubers, and gelatinous beasts into edible meals, applying real-world culinary techniques to make the inedible palatable.

After being rescued and brought to the royal castle, Kengo's secret identity is discovered by the stepmother queen, who reveals that the only known path back to his original world lies in marrying the current king and becoming the official royal consort. Forced into a political marriage, Kengo now inhabits the role of queen while retaining his middle-aged male consciousness, a fact that creates constant comedy and tension as he navigates court life, formal banquets, and diplomatic events. The king, Matthias, gradually becomes a genuine ally, sharing Kengo's mission to reform the kingdom's restrictive food culture.

The narrative follows several major arcs. In the early survival chapters, Kengo and Auguste struggle to find food in the wilderness, culminating in the creation of a makeshift meal from a slain wyvern. After reaching the capital, a hidden cooking session is exposed by the stepmother, leading to the revelation about the marriage condition. Later arcs see Kengo traveling with the king to the forest capital of Vendemia, where a legal trial over the banned consumption of a monster called the Catoblepas forces him to publicly demonstrate the safety and deliciousness of monster cuisine, earning the enmity of the Church and its powerful bishop, Isidoros. A mysterious infectious disease breaks out during a royal deer hunt, and Kengo must combine his medieval cooking knowledge with the princess's lingering memories to concoct a treatment. The final storylines involve a conspiracy between the Church and hostile nobles to have the queen tried for heresy, forcing Kengo to clear his name while confronting the true nature of his reincarnation and the two saints whose writings may hold the key to returning home. Throughout the story, Kengo's pragmatic, middle-aged perspective and his unwavering dedication to good food drive the plot, as he slowly earns the trust of the court and aims to normalize the consumption of monster ingredients across the kingdom.