"FLCL" is a six-volume manga series that blends surreal comedy, science fiction, and coming-of-age themes. The story centers on Naota Nandaba, a 12-year-old boy living in the fictional town of Mabase. His mundane life is disrupted when Haruko Haruhara, a mysterious and eccentric woman riding a Vespa, crashes into him with her guitar. This encounter leaves Naota with a peculiar bump on his head, which later becomes a portal for giant robots to emerge. These robots, often piloted or controlled by Naota, are linked to the enigmatic organization known as Medical Mechanica, which seeks to flatten the world into uniformity.

Haruko, who claims to be an alien investigator, inserts herself into Naota's life, working at his father's bakery and frequently causing chaos. Her true motives remain ambiguous, but she is revealed to be searching for the Pirate King Atomsk, a powerful space pirate whose energy she seeks to harness. Throughout the series, Naota struggles with his feelings of inadequacy, jealousy, and confusion, particularly in relation to his older brother Tasuku, who has left for America to play baseball, and Mamimi Samejima, Tasuku's ex-girlfriend who forms a complicated bond with Naota.

The narrative explores themes of adolescence, identity, and rebellion, often through surreal and absurd scenarios. Naota's interactions with Haruko and the robots force him to confront his emotions and grow beyond his initial passivity. The series also delves into the dynamics of Naota's relationships with his family, friends, and the broader community, all while maintaining a fast-paced, chaotic tone. The story concludes with Haruko departing Mabase, leaving Naota changed but still grappling with the complexities of growing up. The manga's blend of humor, action, and introspection creates a unique and memorable narrative experience.