"Fumoon" is a science fiction anime series that explores themes of environmentalism, human-alien relations, and the consequences of nuclear experimentation. The story is set in a near-future Earth where humanity faces the repercussions of unchecked technological advancement and environmental degradation. The narrative centers on the emergence of a new species, the Fumoon, who are humanoid beings with psychic abilities. These beings are the result of genetic mutations caused by nuclear radiation, and they possess advanced intelligence and a deep connection to nature.

The protagonist, Shingo Tamai, is a young boy who becomes entangled in the conflict between humans and the Fumoon. Shingo's life takes a dramatic turn when he encounters a Fumoon named Fumio, who reveals the existence of their kind and their struggle for survival. The Fumoon, despite their peaceful intentions, are perceived as a threat by humans, leading to escalating tensions. Shingo, along with his sister Keiko and a group of allies, becomes a mediator between the two species, striving to prevent a catastrophic war.

The plot delves into the ethical dilemmas surrounding humanity's treatment of the environment and the moral implications of scientific experimentation. The Fumoon, as a species, embody the consequences of humanity's actions, serving as a mirror to the destructive tendencies of human civilization. The series also examines the fear and prejudice that arise when faced with the unknown, as humans react with hostility and paranoia toward the Fumoon.

Key characters include Dr. Yamano, a scientist who studies the Fumoon and advocates for coexistence, and General Kato, a military leader who views the Fumoon as a threat to national security. Their opposing perspectives drive much of the conflict, highlighting the struggle between scientific curiosity and militaristic pragmatism. The narrative builds toward a climactic confrontation, where the fate of both species hangs in the balance, ultimately questioning whether humanity can overcome its destructive instincts to forge a harmonious future.

"Fumoon" is a thought-provoking series that intertwines speculative science fiction with social commentary, presenting a compelling exploration of humanity's relationship with nature and the unknown.