Timeline of the "Mass Effect" Trilogy Quiz

Spectres were an organization that worked for the Citadel Council, the overarching galactic political body. They had carte blanche to protect the stability of the galaxy and the interests of the council. Humans, as a relatively new species to galactic politics, did not yet have a member on the council or in the Spectres. It was a major political event when Commander Shepard became the first human to join the ranks. After playing the introduction of the first game the player was given more choice to explore the galaxy how they wished, which was in-line with a Spectre being able to do whatever they wanted.

Captain Anderson, Shepard's commanding officer and mentor, was a candidate for the Spectres when he was younger, but didn't make it because of politics. That story was told in the prequel novel "Mass Effect: Revelation" by Drew Karpyshyn (the lead writer of the game).

Shepard's mission in the first game, after becoming a Spectre, was to track down the rogue Spectre Saren. There were a number of leads that could be followed in any order, including meeting with Liara T'Soni, an expert on the protheans, and the daughter of Saren's second-in-command, Lady Benezia. Liara was not colluding with her mother or Saren, and asked to join Shepard to help stop them.

Sovereign was a reaper, an ancient mechanical race the size of battleships that wiped out galactic civilizations every 50,000 years. Saren was merely a puppet of Sovereign. Sovereign was the final boss of the first "Mass Effect" game.

During the prologue of "Mass Effect 2", Shepard's ship, the Normandy, was destroyed, and Shepard suffered massive injuries. Cerberus recovered the body of the presumed-dead commander and brought it back to life for their own purposes. Shepard woke up two years later, where the story of "Mass Effect 2" began.

The antagonists for the middle installment were the Collectors. They were known for looking for interesting genetic anomalies among the other species of the galaxy, and otherwise being very secretive. In "Mass Effect 2", they had turned their efforts to harvesting large numbers of humans for some unknown purpose, but they explicitly hit fringe colonies like Horizon in the Terminus Systems, which were outside of the protection of the Systems Alliance (the pan-human government).

At about the one-third mark in the game, Shepard went to the planet Horizon to stop the Collector attack, where they met one of their former squad mates from the first game.

The final mission of "Mass Effect 2" was the suicide mission. The whole game was about recruiting members to go on the mission, and otherwise preparing. The mission involved making a blind jump through the Omega 4 mass relay to the Collector homeworld, which no one had ever returned from.

After two games of Shepard trying to warn the galactic community about the Reaper threat and being ignored, the Reapers showed up on Earth at the very beginning of "Mass Effect 3". The rest of the game would have Shepard putting together a coalition to help retake Earth from the Reapers.

The strongest military in the galaxy were the turians, but they were dealing with Reaper problems of their own, so were unable to help Earth. If they had help from the krogan, then they might be able to do something. The krogan, for their part, were willing to help if the Genophage (a sterility plague to keep their numbers in check) was cured.

Shepard's first task was to navigate the tricky politics of the Genophage to secure krogan, turian, and possibly salarian support for the war effort.

The quarians had the largest fleet in the galaxy, which would have been very helpful against the Reapers if they hadn't decided to retake their homeworld from the geth, the synthetic race they had created 300 years earlier. Shepard could secure the help of either the quarians or the geth against the Reapers (or both, depending on the decisions made in the current game and the previous games).

All the species in the galaxy working together would still not have been enough to take down the Reapers with brute force; they needed an edge. Schematics for a massive but relatively simple anti-Reaper weapon were discovered in old prothean data archives, which was then built over the course of "Mass Effect 3." At the end of the game Shepard could fire the weapon with slightly different effects, which were colour-coded. This "choose-your-colour" ending was widely derided at the time of release. An "Extended Cut" DLC was released to address some of these concerns, but the infamy of the "Mass Effect 3" ending persisted.

There was a fourth option to not fire the weapon and let the Reapers have another successful cycle.