As part of the Arks Special Planetary Exploration Group Alter, the player is on a journey to return alive from Machia, a chaotic planet where photons have no effect, after the Delta Valiant warship crashes on Machia with 1,000 crew on board. The planet also happens to be home to the Gigantes, who are hostile foes. On the planet exists another source of energy known as Gran, and by substituting it as an energy source in place of photons, technology such as weapons can be used. Source: Wikipedia, "Phantasy Star Nova", available under the CC-BY-SA License.