"Yuyushiki" is a slice-of-life comedy anime centered around the daily lives of three high school girls: Yuzuko Nonohara, Yukari Hinata, and Yui Ichii. The narrative unfolds through their interactions, often revolving around mundane yet humorous situations, as they navigate school life, friendship, and their shared membership in the Data Processing Club. The club, which they join early in the series, serves as a backdrop for their quirky conversations and activities, though it rarely involves serious data processing. Instead, the girls use the clubroom as a space to engage in playful banter, random musings, and lighthearted experiments.

Yuzuko is the most energetic and mischievous of the trio, often initiating absurd or nonsensical discussions. Her cheerful and carefree personality contrasts with Yukari, who is more reserved and prone to overthinking, often reacting with deadpan humor or exasperation to Yuzuko's antics. Yui, the most level-headed of the group, frequently acts as the mediator, balancing Yuzuko's exuberance and Yukari's sarcasm. Despite their differing personalities, the three share a strong bond, and their chemistry drives much of the series' humor and charm.

The episodic structure of "Yuyushiki" lacks a central overarching plot, instead focusing on self-contained vignettes that highlight the girls' interactions. These vignettes often explore themes of curiosity, absurdity, and the joy of everyday life. The humor is derived from their exaggerated reactions to trivial matters, wordplay, and the occasional surreal twist. While the series primarily emphasizes comedy, it also subtly portrays the warmth and comfort of their friendship, making it a lighthearted and relatable portrayal of adolescence.

Supporting characters, such as their classmates and teachers, occasionally appear to add variety to the narrative, but the focus remains firmly on Yuzuko, Yukari, and Yui. The series captures the essence of high school life through its emphasis on small, memorable moments rather than dramatic events, creating a relaxed and enjoyable viewing experience.