Kasumi Mugino works as a writer for a women's magazine, but she carries a secret from her past that she desperately wants to keep buried. One day, she loses a photo connected to that past and frantically searches for it. In her panic, she stumbles upon a startling sight: her boss, Hibiki Hasegawa, calmly making sweets. This discovery shocks her because Hibiki has a fearsome reputation at the company, known as a demon boss whom everyone avoids. Caught off guard, Kasumi accidentally cries out and is discovered by him, setting off a chain of events that reveals his hidden true nature.

Beneath his intimidating exterior, Hibiki Hasegawa is secretly shy and has a deep love for desserts, a combination that Kasumi comes to find endearing rather than frightening. The central conflict of the manga revolves around Kasumi's growing awareness of her boss's sweet, tsundere personality and her own desire to bring out that softer side of him, to make the demon boss blush. Set in a contemporary office workplace, the story unfolds as Kasumi navigates her professional duties while also uncovering more of Hibiki's hidden hobbies and bashful reactions. Their relationship develops through a series of comedic and tender moments, gradually evolving from a simple workplace dynamic into a romantic connection, as Kasumi learns to see past Hibiki's harsh mask and he learns to trust her with his gentler self.