[Shuusou Gyoku is a vertical-scrolling danmaku shoot 'em up, and is the first official game in the Seihou Project]

The game takes place on Earth in the future. The environment had nearly been destroyed, and humanity was on the verge of destruction.

However, the Cactus Company perfected an energy source more powerful than the atomic energy. They used this power, known as cactus energy, to stop the ruin of Earth. However, this energy was very unstable, and caused large accidents. Eventually, it was controlled, and humanity began to prosper once again.

Decades later, VIVIT, a robot "maid-type" powered by this energy, heads out to do errands for her master.