Get caught up before Mass Effect 3
Mass Effect is complex. There are double-crossers, extinct species, complex political motivations, and ships shaped like cuttlefish. And if you havent downloaded all the DLC, or even just played the last two games for a while, Mass Effect 3 is going to be, like, really confusing.
Luckily, the smartest Krogan this side of the Citadel (well explain what those are) has compiled a list of everything you need to know before saving the galaxy once again. By the way, if you have any interest in being surprised by these events (ie, you havent played ME1 or ME2), this list contains spoilers. Obviously.
The Citadel is the Milky Ways U.N. Building
In the future, humanity reaches the stars, and when we get up there we find the Citadel, which is filled with aliens that greet us with open arms. And fear. And mistrust.
The Citadel is essentially a gigantic space station floating in the galaxy, and its loaded with little cute green bugs called Keepers that pretty much run the place. But heres the kicker: its like 50 millenia old, and no one knows where it came from. Space-faring aliens found it, said Huh, this looks cool, and decided to set up shop.
Many think that the Citadel was actually made by the Protheans (who well get to later), but guess what? Thats not true. It was actually created by the Reapers to facilitate total galactic genocide. Honestly, pretty disappointing.
The Council is stubborn
The Citadel Council forms the Citadel government. Their decisions have vast-reaching consequences, and they are incredibly deliberate in their decision-making. They employ the Spectres to retain peace throughout the galaxy. They are the single most important governing body in Mass Effect. They are horribly, horribly inefficient.
The Council slow plays everything. When told that one of their Spectres has gone rogue, they deny it until more evidence can be brought against him. When told that a Reaper is coming to attack the Citadel, they take the wait and see approach. When presented with insurmountable evidence that the galaxy is about to end, they take a coffee break.
This frustration compiles over and over again. Eventually, at the end of ME1, youre given the choice to save them or let them be destroyed. If they were destroyed, a new council takes over in ME2 - and they hate you. If you saved them, they still dont really like you. They really are twits, the lot of them.
Spectres are intergalactic super cops
The Citadel Council ordains a small group of authorities to preserve galactic stability at all costs. That means as a Spectre you're given, quite literally, a license to kill, because there is no better way to preserve the peace than to ruthlessly destroy any obstacles in your way. Poof. Peace accomplished.
As you can imagine, this means the selection process is rather, well, complicated. Faced with rising charges of "that's racist," the Council eventually elected its first human Spectre, one Commander Shepard, in 2183.
The Quarians made the Geth, and now the Geth are like the Cylons
The Quarians are a technologically advanced humanoid race. So advanced, in fact, they created a little robotic Artificial Intelligence called the Geth. But they instantly got freaked out at how awesome the Geth looked, and tried to destroy them. (Probably not the full story - the Geth were also very strong, and very smart).
The Quarians lost the battle and were driven from their own home world. They now survive on fleets of ships called the Migrant Fleet.
In Mass Effect 1, a Quarian named Tali joins your team on a Quarian ritual called a pilgrimage. She rejoins the party in ME2, and your decisions in determine whether Tali is exiled from her people, and whether she wants anything to do with you in ME3.
But some Geth are actually friendly
Despite being one of the chief evil forces in ME1, the Geth arent entirely bad.
The Reaper Nazara (Sovereign) asked the Geth to join forces. Many dismissed the offer, but some joined. These Geth operated under double-cross Spectre Saren Arterius and were known as the Heretics. Kind of reminiscent of Halos Arbiter. No, wait, exactly like Halo's Arbiter.
After Commander Shepard destroys the Reaper Nazara, the good-guy Geth become interested in him, and send a free-thinking Geth agent, comprised of 1183 programs (as compared to the normal dozen or so), out to find him. You have the choice to let this Geth - named Legion - join your team in Mass Effect 2. Or you can just leave him in a box and never turn him on, if youre more a fan of leaving him in mint condition.
Reapers are giant robots that want to (and can) kill everything
The Reapers have been around for a long, long time. Longer than the Protheans. They hibernate in starless spaces in the galaxies, before returning to harvest all sentient life. Why do they harvest sentient life? We have no idea. Maybe because its awesome and evil.
The actual reason is a little more confusing. Potentially as a reproductive cycle to build new Reapers (out of - get this - liquefied life forms). Partly to steal technology developed by the now reapd races. Partly because they really are just that rude.
They dont just look like organic ships, either. The Reaper Vanguard (the Reaper that doesnt hibernate with the rest, instead waiting for the ideal time to signal the return of the other Reapers) was actually used by Saren as his ship.
It started turning him and impairing his ability to make decisions that werent betray the galaxy. That Reapers name was Sovereign, and he was a real jerk. He also looked like a giant Reaper Cuttlefish.
The Reapers have thought this out. Theyve left Mass Relays (like slingshots for space ships) all over the galaxy, and these mass relays all point toward the mysterious, functioning Citadel. That way organic life bases their civilization around the Citadel.
Protheans were an ancient race that were reaped by the Reapers
Protheans were an intelligent race that were harvested in the last reaping. Due to their advanced scientific accomplishments they were incorrectly credited with the creation of Mass Relays and the Citadel. Their ruins are immensely valuable for scientific study.
During the last harvest, a small cluster of surviving scientist Protheans figured out the link between the Citadel, the Mass Relay, and the Reapers. Before dying off, they were able to disrupt the Citadels signal and record their discoveries - Commander Shepard would find the data on the planet Ilos.
But what of the other Protheans? Millions upon millions were, well, liquefied to make a new Reaper. When this attempt likely failed, not all the Protheans were destroyed. The same indoctrination techniques used to physically and mentally alter Saren were used on the Prothean slaves.
Eventually these slaves were genetically modified into a new species, the Collectors.
...and you destroyed them
The Collectors were a mythical species and many doubted their very existence. They resided in dark space, only accessible from the Omega 4 relay (a relay in which no ship had ever returned).
For 50,000 years, the Collectors would collect things ranging from technology to individuals of a particular species. However, the Collectors presented a massive threat during the events of Mass Effect 2, in which they began collecting thousands upon thousands of humans.
It is eventually discovered that these humans were being liquefied to create a really silly looking Human-Reaper. It was weird looking, and Commander Shepard and Co. were forced to destroy it.
At the end of Mass Effect 2, Commander Shepard and his team wipe out all of the Collectors in the entire base. Ha ha.
Saren was indoctrinated by the Reapers
Saren Arterius is a powerful Turian Spectre, who was known for his ruthless tactics, and proven track record. But he is also a rogue Spectre who allied with the Reapers to save biological life.
He figured that if sentient life bowed to the Reapers will, they would be spared - at least as slaves. While his intentions were originally good(ish, hes known for his intense hatred of other species - especially humans), the effect of being in close proximity to the overwhelming evil of the ship takes a toll on him. This process is called indoctrination and it transforms him into a heartless, robotic jerk.
Krogan look like turtles and they hate everyone
Like Raphael. Except the Krogan have a good reason. The Krogan are suffering from a genophage - meaning they're so infertile they're being bred out of existence. To make matters worse, just about everyone from the Salarians to Commander Shepard has had a hand in the genophage. This, it seems, has given them ample reasons to hate the universe.
So why'd it happen to these lizardy bipeds? Because they were too strong. After being riled up by other races to help end the Rachni Wars, the Krogan grew in such substantial numbers they became a threat to everyone. The Salarians created a genetic infection that made them far less fertile - but it was too much, and the Krogan have been dwindling to minuscule numbers ever since. They're not happy.
The Rachni are either extinct, or helping wage war on the Reapers
The Rachni were a bunch of big bugs that terrorized the galaxy before being destroyed by the Krogan. That is, until a small group of scientists find an egg in a drifting ship and bring it to their lab for study. This goes about how youd expect.
Soon Rachni have taken over the lab, but a fully matured queen explains to Commander Shepard that they have been driven insane by being removed from her presence. In an oddly moving moment, she asks what you will do with her.
Commander Shepard can let the queen free or destroy her (effectively destroying all known traces of the Rachni). Regardless of his decision, you run into more of the shrimp-headed bugs.
But if you chose to save the bugs, in ME2 youre contacted by a mysterious Asari who has a message from the queen. The Rachni have progressed quickly and are waiting to wage war on the Reapers.
SSV Normandy SR-1 was destroyed
That's your ship. It's stealthy and incredibly fast. Presumably because they saved cargo weight by replacing the pilot's bones with glass (poor taste!).
It was shot down and destroyed in the beginning of Mass Effect 2. A racist bad guy group called Cerberus rebuilt the ship, with significant improvements - including an artificial intelligence system and much more space. It is now dubbed the SR-2.
Shepard died once
When the Normandy SR-1 was shot down in the beginning of Mass Effect 2, the crew sustained serious losses - chief of all was Shepard him, or her, self.
Shepard was scooped up by Cerebus, put back together, given an all new high-tech body, and offered re-reinstatement as a Spectre (where people, we can only presume, called him "The Spectre Gadget" behind his back).
Cerberus is bad and racist
The Pro-Human interest group is ill-intentioned, but far from stupid. Cerberus has a long history of terrorist acts, including attempts at turning Rachni into super weapons, and turning a colony into husks.
In one of the biggest narrative stretches in Mass Effect, you are forced to work for Cerberus in ME2. Nevermind the fact you spent half a dozen missions combating them in the previous game.
As Mass Effect 2 progresses, you learn that they also tortured kidnapped children (FOR SCIENCE). They did this behind the back of The Illusive Man, who runs Cerberus. You are given a chance to destroy the decrepit base in a mission with Jack, who was stationed there.
Theres no way to appease the Illusive Man
A man whose only sin is loving humans too much. And then also terrorism. The Illusive Mans almost single-minded motivation to make humans the dominant species has put countless people in danger. But it is also the reason Commander Shepard is brought back from the dead - at extreme cost.
Once Shepard is brought back from the dead, the Illusive Man helps you assemble the strongest team possible, from military hero Jacob Taylor to his own assistant Miranda Lawson.
But that doesnt mean hes much into protecting you. He constantly puts Commander Shepard in harms way for personal gain - including walking Shepard directly into a trap.
At the end of Mass Effect 2, the Illusive Man suggests wiping the base out with a radioactive pulse so the Collector technology can be used against the Reapers. Commander Shepard is presented with two options. He can blow up the base, infuriating the Illusive Man, or do as he says.
This decision is presented as one of the most important in ME2, and will somehow come back to bite us in the ass, regardless of what we chose.
The Mako sort of sucked
The M35 Mako was your ground transportation just about everywhere in ME1. Your company would land in the Mako and drive around, jumping, spinning, but never flipping. This car was unflippable.
The Mako missions were incredibly unpopular among fans (They Mako me crazy!), and in ME2 they were replaced with the ability to scan planets and shoot probes.
The Shadow Broker looked awesome - until you murdered him
The Shadow Broker is an unknown individual who buys and sells information. He sold information to batarian mercenaries who then tracked and killed your teammate Thanes wife.
In a DLC pack called Lair of the Shadow Broker, Commander Shepard and Liara TSoni go in search of the Shadow Broker. What they find is an alien called a yahg who had usurped control from the original Shadow Broker.
After killing the Shadow Broker, former teammate Liara TSoni takes over his position, and promises to help use the vast information at her disposal to gain an advantage against the Reapers.
Husks are a gift from the Reapers
Though the Geth are the ones constantly using Dragons teeth (those huge impaling flagpoles that turn humans into Husks), the technology itself came from the Reapers.
Husks are zombies. They look and act similar to the heavily indoctrinated.
Captain Anderson is awesome
Captain David Anderson is a a war hero, the original Captain of the SSV Normandy, and an all-around good guy.
You are given the option to let Anderson join the Council or give that honor to Ambassador Udina. But Udina is such a colossal pain, its hard to imagine even renegade Shepards are unlikely to pick his alternative.
Regardless of which you pick at the end of Mass Effect 1, Anderson plays a relatively small role in 2. He expresses deep distrust in Cerebus, who you now work for.
Some (or none) of your squad from Mass Effect 2 survived Mass Effect 2
Depending on your actions in Mass Effect 2, all, some, or none of your squadmates may have survived. When you import that save, those deaths/lives carry over. If everyone lived, there's a good chance you'll be hanging out with Jack, Garus, and the crew as you try and save the galaxy.
If everyone died? Well, you're going to be meeting a lot of new people, so that's cool!
Shepard might have killed a few hundred thousand innocent people
Well, or at least that's what some people think. In The Arrival DLC, Shepard travels to a space station to save a scientist. When he returns, an entire star system has been destroyed, along with 300,000 Batarians. We'll spare you the details, but just know that some people hold Shepard responsible, and that's why the third game starts off on Earth, with Shepard being stripped of his Commandership. And his ship. The Normandy. His ship is called The Normandy.