Zero is an android discovered as a stowaway aboard a spaceship piloted by two individuals escaping their war-torn planet. Initially hostile, Zero attempts to seize control of the vessel but ultimately shares the crew's objective: to locate a mythical destination known as the edge of the universe, or virgin space.

Throughout the journey, Zero engages the others in philosophical debates regarding humanity’s nature, critiquing its history of warfare, destruction, and environmental neglect. These discussions intensify when the group encounters a cosmic entity that questions humanity’s worthiness to enter virgin space, presenting visions of its violent past. This encounter transforms Zero from an adversary into an ally, who then collaborates with the crew to demonstrate that humanity holds redeemable qualities deserving of passage.

The character is driven by a deep yearning to reach virgin space, a realm of purity lying untouched beyond the known universe.