In 2315 AD, 15 years after one-fifth of humanity's population migrated to Mars, the first World War broke out on Mars. After the war, Mars' population was halved, and civilization regressed.

To prevent repeating this mistake, the Martian United Nations prohibited the development and possession of weapons, as well as violence. All circulating guns and swords became dummies, and weapons transformed into fashion items. Furthermore, most sports were banned as they evoked violence through human contact, drastically reducing people's entertainment options.

Amidst this, “BusterBall” emerged as a new form of entertainment. It was a race conducted in spherical machines, where the sturdy vehicles guaranteed the safety of their occupants.

By 2355 AD, 40 years after the end of the war, “BusterBall” had gradually transformed. What began as a simple race focused on ranking evolved into battles where machines collided, driven by the intense enthusiasm of a generation unfamiliar with violence. Due to the guaranteed safety of the occupants protected by their machines, and with the aim of controlling public frustration by preserving entertainment, “BusterBall” became the world's only sport where violence and gambling were permitted.

The season champion of “BusterBall” could obtain both an honor so great it earned praise from people worldwide, and prize money equivalent to buying an entire country. Some participated to save their impoverished nations, others for the medical expenses of family members suffering from incurable diseases, and still others simply to revel in the violence, joining this competition from nations across the globe.