"Genshiken" centers on the activities of a college club called the Society for the Study of Modern Visual Culture, or Genshiken for short. The club is dedicated to exploring and indulging in otaku culture, including anime, manga, video games, and cosplay. The narrative begins with Kanji Sasahara, a shy and introverted freshman, joining the club after discovering his passion for otaku hobbies. Through his eyes, the series explores the dynamics of the club and its members, who represent a wide spectrum of otaku interests and personalities.

The club includes characters like Makoto Kousaka, a skilled gamer with a calm demeanor, and his girlfriend Saki Kasukabe, who initially disdains otaku culture but gradually becomes more involved with the group. Other members include Harunobu Madarame, a loud and passionate fan of doujinshi and eroge; Mitsunori Kugayama, a quiet and talented artist; and Kanako Ohno, a cosplayer who often collaborates with the club on various projects. The group also interacts with other clubs and individuals within their college, such as the anime production club and the manga research club, adding layers to their social dynamics.

As the series progresses, the club faces various challenges, including organizing events like Comiket, creating their own doujinshi, and navigating interpersonal relationships. The narrative delves into the struggles and joys of being an otaku, addressing themes of identity, acceptance, and the balance between personal interests and societal expectations. The story also highlights the evolution of the club as new members join and older members graduate, showcasing the transient nature of college life and the enduring bonds formed through shared passions.

"Genshiken" provides a detailed and realistic portrayal of otaku culture, blending humor, drama, and slice-of-life elements. The series captures the essence of a niche community while remaining accessible to a broader audience, offering insights into the hobbies and lifestyles of its characters without resorting to stereotypes or caricatures. Through its exploration of the club's activities and the personal growth of its members, "Genshiken" presents a nuanced and engaging depiction of modern otaku culture.