"Yoshida Katsuko no Yabai wa! SDGs Araburu! Trouble! Sustainable!" centers on Yoshida Katsuko, a high school student who becomes unexpectedly involved in promoting the United Nations' Sustainable Development Goals (SDGs). The narrative begins when Katsuko, initially indifferent to global issues, encounters a mysterious transfer student named Aoi Shizuka, who is deeply passionate about sustainability. Aoi introduces Katsuko to the SDGs, sparking a series of events that intertwine their lives with the broader mission of addressing global challenges.

The story unfolds through episodic arcs, each focusing on a specific SDG, such as climate action, gender equality, and responsible consumption. Katsuko and Aoi, along with their classmates, tackle real-world problems within their school and community, often encountering resistance or misunderstandings from peers and adults. The series blends humor, drama, and educational elements, presenting complex issues in an accessible manner. Katsuko's growth is a central theme, as she evolves from a passive observer to an active participant in creating positive change.

Supporting characters include Taro Nakamura, a skeptical classmate who gradually becomes an ally, and Ms. Fujimoto, a teacher who mentors the students in their efforts. The series also features recurring antagonists, such as corporate figures or bureaucrats, who represent systemic obstacles to sustainability. Through teamwork, creativity, and perseverance, the characters devise innovative solutions to these challenges, often drawing parallels to real-world initiatives.

The narrative emphasizes collaboration and the idea that small, localized actions can contribute to global progress. It balances lighthearted moments with serious discussions about the urgency of addressing environmental, social, and economic issues. By the end of the series, Katsuko and her friends inspire their school and community to adopt sustainable practices, leaving a lasting impact on their surroundings. The story concludes with a sense of hope and a call to action, encouraging viewers to reflect on their own roles in achieving the SDGs.