"Kusogette Iuna!" centers on Iuna, a high school girl who is exceptionally skilled in martial arts but struggles with her unkempt appearance and lack of social grace. Despite her rough exterior and abrasive personality, Iuna harbors a deep desire to become more feminine and refined, often clashing with her natural tendencies. The story explores her attempts to navigate the complexities of adolescence, balancing her tough demeanor with her aspirations for personal growth.

The narrative unfolds through Iuna's interactions with her classmates, particularly her childhood friend, Rintaro, who often finds himself caught in the crossfire of her impulsive actions. Rintaro serves as a grounding presence, offering support and occasional criticism as Iuna grapples with her insecurities and ambitions. Their dynamic is a mix of camaraderie and tension, reflecting the challenges of their evolving relationship.

As the series progresses, Iuna's journey is marked by humorous and heartfelt moments, highlighting her efforts to improve herself while staying true to her identity. The manga delves into themes of self-acceptance, friendship, and the pursuit of personal goals, presenting a relatable and often comedic portrayal of teenage life. The supporting cast, including classmates and rivals, adds depth to the story, creating a vibrant and engaging high school setting. Through its blend of action, comedy, and character development, "Kusogette Iuna!" offers a compelling exploration of growth and resilience.