"The Mouse and His Child" is an anime adaptation of the 1967 novel by Russell Hoban, centering on the journey of two wind-up toy mice—a father and son—who seek autonomy and a place to call home. The father mouse is a determined and protective figure, while the child mouse embodies innocence and curiosity. After being discarded by their owner, the pair find themselves in a harsh and unpredictable world, encountering both allies and adversaries as they strive to achieve their goals.

The narrative begins with the mice being sold from a toy shop and eventually breaking, leading to their abandonment. They are discovered by a tramp who repairs them, setting them on a path of self-discovery and survival. Their primary objective is to become self-winding, a metaphor for independence and self-sufficiency. Along the way, they face numerous challenges, including encounters with a manipulative rat named Manny, who seeks to exploit them for his own gain. Manny serves as a recurring antagonist, embodying greed and control.

The mice also form alliances with other characters, such as a philosophical muskrat named C. Serpentina and a fortune-telling frog named Madame Frog. These characters provide guidance and support, helping the mice navigate their journey. The story explores themes of perseverance, family, and the search for identity, as the mice confront both external obstacles and internal doubts.

The setting shifts between various locations, including a junkyard, a pond, and a war-torn battlefield, each representing different stages of the mice’s growth and challenges. The junkyard, in particular, serves as a pivotal location where the mice encounter a group of discarded toys who dream of a utopian society, reflecting broader themes of hope and resilience.

As the mice progress, they learn to rely on each other and their newfound friends, gradually moving closer to their goal of self-winding. The climax involves a confrontation with Manny and his forces, culminating in a resolution that underscores the importance of unity and determination. The series concludes with the mice achieving a sense of belonging and purpose, having transformed from fragile, dependent toys into symbols of resilience and independence.