The Delta Variant is one of the most advanced warships in the Arks fleet—and it has just crashed on the surface of Machia, a planet where photons do not function. A thousand crew members are now stranded, trapped on terrain that makes their standard equipment useless. You are part of the Arks Special Planetary Exploration Group Alter, and the mission is to survive Machia long enough to find a way off. The planet's native population of Gigantes—enormous, highly hostile creatures—has no interest in helping.