"Grimm's Fairy Tales" is an anime series that adapts classic European folktales collected by the Brothers Grimm, reimagining them with a unique narrative framework. The story unfolds in a world where fairy tales are not mere stories but real events that have occurred in a distant past. These tales are preserved in a magical book known as the Fairy Tale Book, which holds the power to bring the stories to life. The central plot revolves around two siblings, Yuki and his younger sister, Marie, who stumble upon this enchanted book in their grandmother's attic. Upon opening it, they are transported into the world of the fairy tales, where they become active participants in the stories.

Yuki and Marie encounter a variety of characters from well-known Grimm tales, such as Cinderella, Snow White, Little Red Riding Hood, and Hansel and Gretel. Each episode typically focuses on a specific tale, with the siblings often finding themselves in the midst of the story's conflicts. The series explores the darker and more complex aspects of these tales, staying true to the original tone of the Grimm brothers' work, which often included moral lessons and cautionary elements. The siblings must navigate these perilous narratives, often relying on their wits and courage to resolve the conflicts and ensure the stories reach their intended conclusions.

Throughout their journey, Yuki and Marie are guided by a mysterious figure known as the Storyteller, who serves as a narrator and occasional mentor. The Storyteller provides context and insight into the tales, helping the siblings understand the deeper meanings and lessons embedded within each story. As the series progresses, it becomes evident that the Fairy Tale Book is more than just a collection of stories; it is a living entity with its own agenda, and the siblings' actions within the tales have far-reaching consequences.

The anime blends episodic storytelling with an overarching narrative, as Yuki and Marie's journey through the fairy tales gradually reveals a larger mystery surrounding the origins and purpose of the Fairy Tale Book. The series maintains a balance between the fantastical elements of the fairy tales and the emotional growth of the siblings, who learn valuable lessons about morality, resilience, and the power of storytelling. By the end of the series, the siblings' experiences within the tales culminate in a resolution that ties together the individual stories and the overarching plot, providing a satisfying conclusion to their adventure.