"Kimi to Ayumu Nichijō" centers on the daily interactions between Tanaka, a high school student and member of the school's shogi club, and Ayumu, a first-year student who joins the club. The narrative explores their evolving relationship, blending elements of slice-of-life and romantic comedy. Tanaka, though older, is often outmatched by Ayumu's shogi skills, creating a dynamic where she frequently teases him. Despite her playful demeanor, Ayumu harbors feelings for Tanaka, which she subtly expresses through her actions and words.

The story progresses through a series of episodic chapters, each highlighting moments of their shared routine, shogi matches, and school life. Ayumu's straightforward yet enigmatic personality contrasts with Tanaka's more reserved and occasionally clueless nature, leading to humorous and heartwarming situations. Their interactions are punctuated by Ayumu's habit of making bold statements or gestures, often leaving Tanaka flustered but increasingly aware of her affection.

Supporting characters, such as their classmates and fellow club members, add depth to the narrative, providing additional perspectives and comedic relief. The shogi club serves as a central setting, where the characters bond over their shared interest in the game, though the focus remains on the interpersonal dynamics between Tanaka and Ayumu. The manga balances lighthearted humor with moments of genuine emotional connection, capturing the nuances of a budding romance within the framework of everyday life.