Mass Effect 2 Story Explained: Plot Summary and the Suicide Mission

Mass Effect 2 is the second game in BioWare's trilogy, released in 2010 and set mostly in 2185, two years after the first game. It's a darker, more personal story: Shepard dies, comes back working for a group Shepard used to fight, and spends the game recruiting a team for a mission nobody expects to survive. Many outcomes depend on the player, and this page describes them as choices rather than a fixed version. It contains full spoilers. (Mass Effect 2)

Before the story begins#

At the end of Mass Effect, Shepard stopped Saren and destroyed the Reaper Sovereign in the Battle of the Citadel. The rest of the Reapers are still in dark space, and the Citadel Council has decided to call Sovereign a geth warship. Cerberus, a human-first group Shepard ran into as terrorists in the first game, believes Shepard is humanity's best hope. A save from the first game carries Shepard's choices forward, including who survived Virmire and what happened to the Council. The Mass Effect timeline places all of this in order. (Mass Effect; Mass Effect 2)

Death and the Lazarus Project#

The game opens in 2183, weeks after the Citadel battle, with the Normandy SR-1 hunting geth stragglers. An unknown ship tears it apart. Shepard gets most of the crew to the escape pods and goes back for the pilot, Joker, puts him in the last pod, and is blown into space. Shepard suffocates and the body falls to the planet below. (Mass Effect 2)

Two years later Shepard wakes in a Cerberus lab. The Lazarus Project, run by Miranda Lawson, has rebuilt Shepard from the remains with cybernetics, at enormous cost. The station is under attack from a traitor, and Shepard escapes with Miranda and Jacob Taylor to meet their boss, the Illusive Man. His pitch is direct: human colonies in the Terminus Systems are being emptied, the Alliance and the Council won't help, and Cerberus thinks the Collectors, a secretive race rarely seen outside the Omega 4 Relay, are behind it. (Mass Effect 2)

At the empty colony of Freedom's Progress, Shepard meets Tali'Zorah again and finds proof that the Collectors took everyone, using insect-like Seekers that paralyse their victims. Cerberus gives Shepard a new ship, the Normandy SR-2, with Joker at the helm, Dr Karin Chakwas in the medbay and an AI, EDI, built into the hull. (Mass Effect 2)

Building the team#

The Illusive Man hands Shepard a list of names. On Omega, the lawless station run by Aria T'Loak, Shepard recruits the salarian scientist Mordin Solus, who is fighting a plague in the slums, and a vigilante called Archangel, who turns out to be Garrus Vakarian. From a prison ship Shepard frees the biotic convict Jack. On Korlus the krogan warlord Okeer dies and leaves behind a tank-bred krogan, Grunt. On Illium Shepard finds the drell assassin Thane Krios and the asari justicar Samara. The mercenary Zaeed Massani and the thief Kasumi Goto can also join. (Mass Effect 2)

On Horizon Shepard sees a Collector attack in person, and fights off the abduction with Mordin's countermeasure against the Seekers. The Virmire survivor, Kaidan or Ashley, is stationed there and refuses to trust Shepard while Shepard works for Cerberus. Shepard also learns that the Collectors seem to want Shepard specifically, and that the Illusive Man may have used Horizon, and Shepard, as bait. (Mass Effect 2)

Each crew member has unfinished business, and helping settle it earns their loyalty. Miranda protects her sister. Mordin faces his part in the genophage and his former student Maelon. Thane reaches his estranged son Kolyat. Samara hunts her daughter Morinth, and Shepard can let Morinth take Samara's place instead. Tali stands trial before the Migrant Fleet after her father, Rael'Zorah, dies running secret experiments on geth. (Mass Effect 2)

The Collectors and Harbinger#

The Illusive Man sends Shepard to a disabled Collector ship, which turns out to be a trap. Inside, EDI compares Collector DNA with Prothean data and finds a match. The Collectors are Protheans, rewritten by the Reapers after their defeat into a servant race. Their leader, the Collector General, is a puppet for a Reaper called Harbinger, which can take direct control of any Collector. The ship is the same one that destroyed the first Normandy. (Mass Effect 2)

To use the Omega 4 Relay and survive, the Normandy needs a Reaper's identification signal. Shepard finds one on a dead Reaper being studied by a Cerberus team, who have all been indoctrinated or killed. There Shepard finds a geth that uses a piece of Shepard's old armour as a patch. If Shepard reactivates it rather than handing it to Cerberus, EDI names it Legion, and Legion explains that most geth want nothing to do with the Reapers and that the geth who followed Saren were a breakaway faction, the heretics. (Mass Effect 2)

Installing the signal gives the Collectors a way in. While Shepard is away, they board the Normandy and take the entire crew except Joker, who has to unshackle EDI to save the ship. How quickly Shepard goes after them decides how many of the crew survive. (Mass Effect 2)

The suicide mission#

The Normandy goes through the Omega 4 Relay, past a graveyard of wrecked ships, and lands inside the Collector base near the centre of the galaxy. Shepard splits the team: a specialist crawls through the vents to open doors, a second team leader holds a corridor, a biotic shields the group from swarms, and someone escorts the rescued crew back to the ship. Who survives depends on the Normandy's upgrades, the team's loyalty and whether Shepard picked the right people for each job. Anyone can die. (Mass Effect 2)

At the heart of the base, the abducted colonists are being liquefied into a human Reaper, a giant skeletal machine still in its larval stage. EDI works out what it means: the Reapers are built from the species they harvest, each one a whole people in a single form. Shepard and two squadmates hold the platform at the core against the Collectors while the rest of the team gets clear. (Mass Effect 2)

The ending explained#

Before Shepard can blow up the base, the Illusive Man calls and asks Shepard to kill the remaining Collectors with a timed radiation pulse and keep the station for Cerberus. Shepard can do that, or destroy the base outright and refuse him. Destroying it means nobody can study the Reapers' technology. Keeping it gives Cerberus what it wants, and in Mass Effect 3 the Illusive Man uses what he learned there. This is the player's choice and the series doesn't treat either option as canon. (Mass Effect 2; Mass Effect 3)

Either way, the unfinished human Reaper then climbs up to attack, and Shepard's team shoots it down. Shepard and the survivors run for the Normandy as the base collapses. With a strong team, everyone can survive. With a weak one, several squadmates die, and if very few make it, Shepard dies too and that save ends there. Back aboard, Shepard has a last exchange with the Illusive Man and can cut ties with Cerberus. (Mass Effect 2)

The final scene leaves the crew behind and shows the Reaper fleet in dark space, waking and turning towards the galaxy. That's the meaning of the ending: destroying the Collectors stopped the Reapers' latest plan, but they don't need a plan any more. They are coming the long way. The open questions are how long the galaxy has and whether Shepard can be trusted after working with Cerberus. (Mass Effect 2)

Two add-ons bridge to the next game. In Lair of the Shadow Broker, Liara T'Soni kills the Shadow Broker and takes over his network. In Arrival, Shepard rescues Dr Amanda Kenson, learns the Reapers are days from entering through the Alpha Relay in the Bahak system, and destroys the relay to delay them. The blast kills more than 300,000 batarian colonists, and Shepard goes back to Earth to face the consequences. (Mass Effect 2: Lair of the Shadow Broker; Mass Effect 2: Arrival)

What it sets up#

Mass Effect 3 opens months later with Shepard grounded on Earth for the Alpha Relay, just as the Reapers arrive. Who survived the suicide mission, what happened to the Collector base, the fate of Legion, and the cure research Mordin saved or destroyed all carry over. The ending is covered on the Mass Effect 3 ending page, and the whole series on Mass Effect story explained. (Mass Effect 3)

Test yourself: take the Mass Effect 2 quiz, twelve questions on the Lazarus Project, the Collectors and the suicide mission. (Mass Effect 2)