[citation needed] The Federacy is all that is left of the Human race, sealed off in protective domes, away from the harsh environment of future Earth.

The Federacy was able to survive so far due to the skills of their hardened commanders, whom must pass the trials of the "Blooding", a live-fire graduation exercise that involves open conflict with the Raak-Zun, to earn their rank.

Six months following his successful graduation from the Blooding, Commander Ethan tardily returns to the Federal Dome to find it under siege from the Raak-Zun, whom breached through the tunnel system.

Under orders from the General, Ethan and his company cross the portal to end up in a lush jungle world, in which the Federals name it "Elysium", but are shortly attacked afterwards by a force of extraterrestrial machines that Lex name "Sentinels".

Ten days after settling themselves in Elysium, Ethan picks up a distress call only to discover the Raak-Zun have also mysteriously managed to arrive to the new planet.

In a final confrontation that even involves the Federal forces using nuclear warheads to push through heavy defenses, Ethan and the General back the Raak-Zun tribal leader, Slavemaster Sauk, into a corner, using Lex into a hostage situation.

It is revealed Sauk, as he returns to his tribe, is immediately arrested by the orders of the Great Oracle, whom perceives him as a heretic and predicts he may provoke the "day of severance", leading to a possible Raak-Zun civil war.

When a border outpost is attacked while Madok conducts a massive assault to the Federal Dome, Sauk takes the chance to lead a counterstrike and restore his honor until he comes across a strange pit, thriving with luminous yellow tentacles.

Afterwards, the Symbiont manages to establish contact with the stranded Sentinel drones on Earth allowing them to repair a portal on their side, allowing the Symbiont to travel to Earth in pursuit of a Parasite, revealed to be the aberration which had gripped Sauk and the Oracle, being discovered as an interplanetary being that travels between planets, leeching life and twisting lifeforms to perform it's bidding, essentially creating the Raak-Zun.

[2] After several patches a number of early bugs have been resolved, and a multiplayer mode introduced, however recent reviews continue to conclude that the game remains mediocre.