"Planetes" is a hard science fiction anime series set in the year 2075, where humanity has expanded its reach into space, leading to the colonization of the Moon and the exploration of distant planets. The story primarily revolves around the Debris Section, a division of the Technora Corporation tasked with cleaning up space debris orbiting Earth. This debris, remnants of decades of space exploration, poses significant risks to spacecraft and satellites, making the work of the Debris Section crucial yet often overlooked.

The protagonist, Ai Tanabe, is an idealistic and enthusiastic new recruit to the Debris Section. Her optimism and strong sense of justice contrast sharply with the more cynical and experienced members of the team. Hachirota "Hachimaki" Hoshino, a skilled debris collector with dreams of owning his own spaceship, serves as a central figure. His pragmatic and sometimes abrasive demeanor often clashes with Ai's idealism, but their dynamic forms the emotional core of the series. Other key members include Fee Carmichael, the laid-back yet competent leader of the team, and Yuri Mihairokoh, a quiet and introspective engineer haunted by a personal tragedy involving space debris.

The narrative explores both the personal and professional lives of the Debris Section crew, delving into their struggles, aspirations, and relationships. As the series progresses, it examines broader themes such as the ethical implications of space exploration, the socioeconomic divide between Earth and space colonies, and the environmental impact of human activity in space. The crew faces challenges ranging from bureaucratic obstacles and corporate politics to life-threatening situations during debris collection missions.

A significant subplot involves Hachimaki's ambition to join a mission to Jupiter, which becomes a driving force for his character development. His journey is marked by personal growth, as he grapples with his fears, relationships, and the sacrifices required to achieve his dreams. Meanwhile, Ai's unwavering belief in the importance of their work inspires those around her, even as she confronts the harsh realities of their often thankless job.

The series balances its episodic structure with an overarching narrative, gradually building tension as the stakes for the Debris Section and humanity's future in space increase. The final arc focuses on the Jupiter mission, tying together the personal and thematic threads of the story. "Planetes" concludes with a poignant reflection on the interconnectedness of humanity's endeavors in space and the enduring spirit of exploration.