Plot Summary

The protagonist is Commander Shepard -- by default he is a male solider, but you can recreate the character as a female and choose a different class as well, I will talk about the different classes a little later. You can choose Shepard's history, his background, his characteristics, and so on. Every decision you make will have an impact on the main plot, so you have to choose carefully.

The game starts with Commander Shepard being sent on an important mission to a planet called Eden Prime. The game is set in the year 2183, Humans are living in harmony (or bitter harmony) with other alien species. The aliens have formed a high council, and humans are not a part of the council. The council has special agents called Specters. The first mission of the game is test for Commander Shepard; if he can prove himself, he'll be honored with the rank of a Spectre. Another Spectre called Nihlus belonging to an alien race called "Turians" is accompanying Shepard on the mission. The mission is going smooth till suddenly Nihlus is found dead, after a little investigation they learn that he was killed by a legendary Turain Spectre called Saren.

Commander Shepard continues on his mission, which includes finding a lost alien beacon. While on mission, he meets a lone surviving marine, Gunnery Chief Ashley Williams; her entire team was attacked and left to die. Shepard learns from Williams that an ancient race called the Geth is behind all the attacks and they wish to acquire the beacon for themselves. Shepard finds the beacon, but it gets activated by mistake. Before destroying itself, the beacon sends a vision to Commander Shepard. This is the initial plot; from here on, Commander Shepard proves to the council that he's a capable marine and should be awarded the rank of a Spectre. What follows throughout is his journey to capture and bring justice to Saren.

As you can see, the plot is very deep, and the game built around this plot is exceptional.