A young count’s daughter named Noish carries a secret: she has memories of her past life as an ordinary Japanese person. Her greatest dream in her current life is simple to live quietly without drawing any attention to herself. Unfortunately for her, that plan crumbles the moment she meets Charles, the heir to the prestigious Meldion ducal house, at a ball. While other young ladies flock to this brilliant high-spec nobleman, Noish remains indifferent. To her horror, she realizes this has triggered the classic shoujo manga flag of Oh, an interesting woman, in Charles’s mind. She is determined to break that flag by any means necessary.

However, Noish accidentally reveals that she possesses memories from a previous life. Far from being scared off, Charles becomes intensely interested. His courtship is aggressively persistent, like that of a loyal but overbearing large dog. After a rather unconventional proposal involving miso soup a taste of home from her Japanese past that moves Charles to tears the two officially become engaged and soon marry.

The story follows this unusual newlywed couple as they navigate noble society together. Noish often finds herself overwhelmed by Charles’s enthusiastic devotion and possessive nature, which frequently leads to passionate and physically intimate encounters between them. A recurring challenge comes from Princess Florens, who also has feelings for Charles. When the couple attends a royal ball hosted by the princess, they must make their marriage known, leading to a dramatic confrontation.

Further arcs introduce other complications. The annoying Prince Eldorado from the neighboring country of Galdia takes a strange interest in Noish, fueling Charles’s jealousy and triggering his explosive possessiveness. In another arc, Noish is separated from Charles to teach etiquette to young ladies in a rural territory. There, she deals with bickering debutantes and a dangerously handsome yet incredibly narcissistic man named Maxim from the Fraimleit family, who tries to seduce her as an insult to Charles. When Maxim crosses the line by insulting her husband, Noish cannot hold back her temper.

Through all these adventures and romantic interludes, the pair only grow closer, balancing their public duties as nobles with their private life as a passionately in love couple. Their story is a comedic and romantic tale of a former Japanese woman and her devoted duke of a husband finding happiness in an isekai fantasy world.