"Hōkago Saikoro Club" centers on a group of high school girls who discover the world of board games and tabletop gaming. The narrative begins with Midori Oono, a reserved and studious first-year student, who stumbles upon the Saikoro Club, a small after-school group dedicated to playing board games. Initially hesitant, Midori is drawn in by the enthusiasm of the club's members, particularly Aya Takayashiki, the club president, and Miki Takekasa, a cheerful and outgoing classmate. As Midori becomes more involved, she begins to appreciate the strategic and social aspects of board games, which contrast with her previously solitary lifestyle.

The series explores the dynamics of the club as they introduce various board games, ranging from classic titles to modern strategy games. Each game serves as a backdrop for character development and interpersonal relationships. The members face challenges such as organizing events, recruiting new members, and competing in local tournaments, which test their teamwork and problem-solving skills. The narrative also delves into the personal lives of the characters, highlighting their growth and the bonds they form through their shared passion for gaming.

Key characters include Midori, whose journey from an introverted student to an active participant in the club forms the emotional core of the story. Aya, the confident and knowledgeable club president, acts as a mentor figure, while Miki provides comic relief and a sense of camaraderie. Other members, such as the quiet but observant Kei and the competitive Shizuku, add depth to the group dynamic. The series balances lighthearted moments with more serious themes, such as overcoming personal insecurities and the value of collaboration.

The plot progresses through episodic arcs, each focusing on a specific game or event, while maintaining an overarching narrative about the club's evolution and the characters' individual journeys. The manga emphasizes the educational and social benefits of board games, portraying them as a medium for creativity, critical thinking, and connection. Through its engaging storytelling and relatable characters, "Hōkago Saikoro Club" offers a thoughtful exploration of friendship, personal growth, and the joy of discovering new interests.