"Hitori Bocchi no Marumaru Seikatsu" centers on Hitori Bocchi, a socially anxious middle school girl who struggles to make friends. After her only friend, Kai Yawara, moves to a different school, Bocchi is tasked with befriending every classmate in her new class before graduation. Kai sets this challenge as a condition for their continued friendship, believing it will help Bocchi overcome her extreme shyness and social awkwardness.

Bocchi’s journey begins at her new school, where she is placed in a class separate from Kai. Her anxiety manifests in comedic and endearing ways, such as fainting from stress or practicing conversations with inanimate objects. Despite her struggles, Bocchi gradually begins to interact with her classmates, each of whom has distinct personalities and quirks. Among them is Nako Sunao, a cheerful and straightforward girl who becomes Bocchi’s first friend. Nako’s patience and kindness help Bocchi take small steps toward socializing.

Other classmates include Aru Honshou, a self-proclaimed "delinquent" who is actually kind-hearted but prone to misunderstandings, and Sotoka Rakita, a transfer student from England who struggles with Japanese culture and language. Bocchi’s interactions with these characters highlight her growth as she learns to navigate social situations, albeit with frequent setbacks and humorous mishaps.

The series focuses on Bocchi’s incremental progress in forming friendships, emphasizing her determination and resilience. Each episode explores her efforts to connect with a new classmate, often leading to heartwarming and comedic moments. The narrative balances Bocchi’s personal struggles with the supportive dynamics of her growing circle of friends, showcasing the importance of understanding and patience in building relationships.

Through its episodic structure, "Hitori Bocchi no Marumaru Seikatsu" portrays Bocchi’s journey as a relatable and uplifting exploration of overcoming social anxiety. The series maintains a lighthearted tone while addressing themes of friendship, self-improvement, and the challenges of stepping out of one’s comfort zone.