Continued from Part 1.
WARNING: Once again this contains spoilers for the Mass Effect story. Do not read this if you have not played the game.
Picture the future in our galaxy. Space-travel is a reality, and we share the galaxy with many alien races. All these races have access to long distance space travel provided by portals created by a ancient alien race. Somewhere in the galaxy exists a large space station where many of the races have embassies so their ambassadors can meet and conclude government. Not to mention business people, tourists and travellers.
Now enter a human protagonist, a man with a strong will who others (human and alien) want to follow. Then a dark alien race begins to emerge that threatens the galaxy. The protagonist vows to fight them, but at one point is killed, and is then miraculously brought back to life.
The dark alien race begins to build up its forces, their true threat to the galaxy is revealed. The protagonist vows to unite all the alien races in the galaxy to fight the dark threat.
The protagonist needs to create peace between the races to build up his forces to fight this overwhelmingly powerful enemy. Then it is discovered, the dark threat is part of a cycle that happens every 10s of thousands of years, to wipe out all life in the galaxy, a cycle of “order” versus “chaos”. Once organic life is wiped out, the dark race once again disappears for millenia and the cycle continues until the younger organic races rebuild their civilizations.
The climax of the story is a huge space battle, where the combined forces of the galaxy led by the protagonist, take on the dark enemy in a battle that will decide the fate of the galaxy.
What I have just described to you is the main story arc from the late-90s TV show Babylon 5.