"Kagaku Bōkentai Tansar 5" is a science fiction anime series that revolves around a team of five young scientists who embark on missions to protect Earth from various threats. The team, known as Tansar 5, operates under the guidance of the International Science Organization (ISO), which is dedicated to solving global crises through advanced technology and scientific expertise. Each member of Tansar 5 specializes in a distinct scientific field, including physics, chemistry, biology, engineering, and computer science, allowing them to tackle challenges with a multidisciplinary approach.

The narrative begins with the formation of Tansar 5, brought together by Dr. Kenzo Kabuto, a renowned scientist who serves as their mentor. The team consists of Ryu, the leader and physicist; Akira, the chemist; Midori, the biologist; Takeshi, the engineer; and Yumi, the computer scientist. Their first mission involves investigating a series of mysterious energy fluctuations threatening to destabilize Earth's atmosphere. As the series progresses, Tansar 5 faces increasingly complex threats, including rogue artificial intelligence, extraterrestrial invasions, and environmental disasters caused by human negligence.

A recurring antagonist is Dr. Hell, a former colleague of Dr. Kabuto who seeks to exploit advanced technology for global domination. Dr. Hell's schemes often involve creating powerful mechanical monsters or manipulating natural phenomena to achieve his goals. Tansar 5 must use their scientific knowledge and teamwork to counteract these threats, often developing new technologies or strategies on the fly. The series emphasizes the importance of collaboration, critical thinking, and ethical responsibility in the application of science.

Throughout the series, the characters undergo personal growth, grappling with the moral implications of their work and the consequences of their actions. Ryu, as the leader, struggles with the weight of responsibility, while Akira faces dilemmas about the dual-use nature of chemical research. Midori's deep connection to biology leads her to advocate for environmental preservation, Takeshi's engineering skills are tested by increasingly complex machinery, and Yumi's expertise in computer science becomes crucial in combating cyber threats.

The episodic structure of the series allows for a variety of standalone adventures, each highlighting a different scientific concept or ethical issue. However, an overarching narrative ties these episodes together, culminating in a final confrontation with Dr. Hell and his ultimate weapon, a planet-destroying device. Tansar 5 must combine their individual strengths and scientific knowledge to prevent catastrophe, reinforcing the series' central theme of science as a force for good when wielded responsibly.