"I Dream of Mimi" centers on Mimi, a young woman who works as a clerk in a small, struggling bookstore in a quiet town. Her life takes an unexpected turn when she begins experiencing vivid, recurring dreams about a fantastical world filled with magical creatures, ancient prophecies, and a looming conflict between light and darkness. In these dreams, Mimi discovers she is the reincarnation of a legendary hero destined to save this world from an encroaching evil known as the Void.

As the dreams grow more intense, Mimi starts to notice strange occurrences in her waking life, such as cryptic messages appearing in books and encounters with mysterious individuals who seem to know more about her than they should. Among them is Kaito, a enigmatic young man who claims to be a guardian from the dream world sent to protect her. Kaito reveals that the boundaries between the dream world and reality are weakening, and Mimi’s role as the hero is crucial to preventing the Void from consuming both realms.

Reluctantly, Mimi agrees to embrace her destiny, embarking on a journey that oscillates between her mundane daily life and the surreal, perilous dream world. Along the way, she forms alliances with other dreamers who share fragments of her memories and abilities, including Rina, a spirited artist, and Haruto, a stoic swordsman. Together, they uncover the truth behind the Void’s resurgence and the ancient betrayal that fractured the dream world centuries ago.

The narrative explores themes of identity, responsibility, and the interplay between dreams and reality. Mimi struggles to reconcile her ordinary existence with the extraordinary demands of her newfound role, often questioning whether she is truly the hero everyone believes her to be. As the story progresses, the lines between her two worlds blur, forcing her to confront her fears and insecurities while preparing for an inevitable confrontation with the Void’s malevolent leader, a figure tied to her past life.

The series balances episodic adventures with an overarching plot, gradually revealing the history of the dream world and the significance of Mimi’s reincarnation. Key moments include the discovery of ancient artifacts that enhance her abilities, battles against Void-corrupted creatures, and emotional revelations about her companions’ ties to the prophecy. The climax builds toward a final showdown where Mimi must harness the full extent of her powers to restore balance to both worlds, though not without personal sacrifices and lasting consequences.

"I Dream of Mimi" presents a blend of fantasy, adventure, and introspection, anchored by Mimi’s journey of self-discovery and her evolving relationships with those who share her destiny. The story’s dual-world structure allows for a dynamic exploration of its themes, while the characters’ growth and the unfolding mystery of the Void keep the narrative engaging and cohesive.