Year 4157. Humanity had to emigrate out of solar system to outlive earth disasters. After centuries wandering space, finally they could arrive at the TRAPPIST-1 solar system where set up and started a new human civilitation.
The chosen exoplanet was rich in uranium, source of energy to begin their new way of life. Unfortunately, they weren't alone in TRAPPIST-1, there were other form of lifes who want to get the same resources of energy for them. In order to get it, they had created control nuclear balls which nulled willpower of the exoplanet natural wildlife.
So, they could reach the natural resources easier.
Uchu Yohei was the chosen human to remove these control balls and reset the natural wildlife in the planet. Bearing just a plasma gun he should return the planet to the human control.