"Ruri Ruri: Futago no Jijō" centers on the lives of twin sisters, Ruri and Ruri, who share the same name but possess contrasting personalities and appearances. The narrative explores their daily lives, relationships, and the unique challenges they face as twins. Ruri, the more outgoing and energetic sister, often takes the lead in their interactions, while the other Ruri is reserved and introspective, creating a dynamic interplay between the two. Their bond is central to the story, highlighting both the joys and struggles of their shared identity.

The plot unfolds through a series of episodic vignettes, each focusing on different aspects of their lives, from school and friendships to family dynamics. The twins navigate misunderstandings, societal expectations, and their own insecurities, often finding humor and heart in their experiences. Supporting characters, including classmates, teachers, and family members, add depth to the narrative, providing additional perspectives on the twins' relationship and individual growth.

Themes of identity, individuality, and the complexities of sibling relationships are woven throughout the story. The twins' journey is marked by moments of self-discovery, as they grapple with the balance between their shared identity and their distinct personalities. The manga balances lighthearted humor with poignant reflections, offering a nuanced portrayal of twinhood and the universal challenges of growing up.