"Shinken Densetsu Tight Road" is a 1990 anime series that blends elements of action, adventure, and science fiction. The story is set in a dystopian future where humanity faces the threat of extinction due to environmental collapse and the rise of monstrous creatures known as "Bio-Monsters." These Bio-Monsters are the result of genetic experimentation gone wrong, and they now roam the Earth, preying on the remnants of human civilization.

The protagonist, Ken Takase, is a young man who becomes the pilot of a powerful combat machine called the "Tight Road." This machine is one of the few remaining weapons capable of standing against the Bio-Monsters. Ken is driven by a personal vendetta, as his family was killed by these creatures, and he seeks to avenge their deaths while protecting what remains of humanity. Alongside Ken is a group of allies, each with their own motivations and backstories, who join him in the fight against the Bio-Monsters.

The narrative unfolds as Ken and his team travel across the devastated landscape, encountering various factions of survivors, each with their own agendas. Some groups are focused on rebuilding society, while others have succumbed to desperation and chaos. The series explores themes of survival, sacrifice, and the resilience of the human spirit in the face of overwhelming odds. As the story progresses, Ken and his allies uncover deeper secrets about the origins of the Bio-Monsters and the true nature of the Tight Road, leading to a climactic confrontation that will determine the fate of humanity.

The series is characterized by its fast-paced action sequences, intricate mecha designs, and a focus on the moral dilemmas faced by its characters. The interplay between the human drama and the larger sci-fi elements creates a compelling narrative that keeps viewers engaged throughout its run.