The fortified city of Feste is the last human stronghold in a hostile world. Its inhabitants now depend on a rare substance called Pluton, which is the only source of magic in this world. However, Pluton in its natural form is highly toxic to humans, but not to the orcs, who routinely mine it and process it into a more usable form. The orc mines are therefore often the target of human expeditions, who take the rare Pluton there and kill everything in their path.

As a total novice, you and other adventurers head underground to find Pluton. But the quest goes awry and you encounter an unexpected evil lurking beneath the surface. You and your new friends must defend themselves and strategize to avoid the toughest enemies.