This page contains a walkthrough for the main missions of Mass Effect 2. Major changes in the gameplay from Mass Effect are listed in the main Mass Effect 2 page, while the effects of importing a saved game from Mass Effect are listed in the Save File Transfer page. Note that if you are playing Mass Effect Legendary Edition, all content that was previously available only from Downloadable Content (DLC) is now included by default, but overall requirements and prerequisites for the content in game remain largely the same.

Prologue[edit | edit source]

Prologue missions take place at the beginning of the game, in mandatory progression. At the end of the prologue Shepard receives command of the Normandy SR-2 and is free to explore both the ship and the galaxy.

Prologue: Save Joker - Story and setting

Prologue: Awakening - Create your Shepard, Tutorial

Freedom's Progress - First mission with Miranda and Jacob

Stop the Collectors - Master mission for the rest of the game

Act 1[edit | edit source]

Act 1 begins when Shepard receives the Stop the Collectors master mission along with command of the Normandy SR-2 and continues until the mission to Horizon, which is activated as soon as Shepard has recruited all four of Mordin, Garrus, Jack, and Grunt. Any other missions and assignments not completed during Act 1 can still be completed during Act 2. Note that the order in which squadmates are recruited during Act 1 is entirely up to Shepard and will not affect how events play out in any way.

You will also have the opportunity to perform various assignments -- some are available on Omega, some on the Citadel, and others you can discover during the process of Planet Scanning. Assignments described as N7 Assignments usually involve squad deployments and combat -- effectively small missions -- and provide experience, credits, and other rewards. All assignments are optional, but they help advance the story and provide the opportunity for additional rewards and items.

Act 1 Dossiers[edit | edit source]

Perform dossier missions to recruit new squad members for your team. It is recommended that you recruit Mordin first so that you will be able to take advantage of upgrades in the Research Lab on the Normandy. When these four missions have all been completed, the Horizon mission will trigger and Act 2 will begin.

Dossier: The Professor - Mordin

Dossier: Archangel - Garrus

Dossier: The Convict - Jack

Dossier: The Warlord - Grunt

Act 1 DLC[edit | edit source]

The following DLC missions and assignments can be performed during Act 1, or saved until Act 2 if desired.

Dossier: The Veteran - Zaeed

Dossier: The Master Thief - Kasumi

Zaeed: The Price of Revenge - Loyalty

Kasumi: Stealing Memory - Loyalty

Overlord

Firewalker Pack

Normandy Crash Site

Act 1 Progression[edit | edit source]

When all four of the original (non-DLC) dossier missions are complete, the Horizon mission will be activated and Act 2 will begin.

Horizon

Act 2[edit | edit source]

Act 2 begins upon successful completion of the Horizon mission. At this point the Normandy is able to travel to Illium and new dossiers and missions become available. New assignments also become available during the course of Act 2 - some at Illium, some on Tuchanka, and many new N7 Assignments open up through Planet Scanning in the new systems which open up for exploration. New merchants also become available, along with new items at some of the Act 1 merchants - see the Merchants Guide for a complete list of locations and wares.

Act 2 Dossiers[edit | edit source]

Four more squadmates can now be recruited, though Legion's mission works differently in that it does not become available until after the Collector Ship mission, and triggers additional act progression. You will need at least eight total crew members, not counting Legion, to advance the plot.

Dossier: The Assassin - Thane

Dossier: The Justicar - Samara

Dossier: Tali - Tali

Reaper IFF - Legion

Act 2 Loyalty Missions[edit | edit source]

Starting in Act 2, speaking with squad members on the Normandy will elicit requests for you to perform Loyalty missions. Securing the loyalty of your squad will both unlock new powers for them and increase the likelihood that they, and indeed Shepard, will survive Act 3. All loyalty missions are optional -- they increase the power of your team but are not required to be completed for the game to progress.

Miranda's and Jacob's missions can be obtained immediately when Act 2 begins. Additional missions become available one at a time in the order listed; if the character whose loyalty mission would normally unlock is not yet present (e.g. Grunt is still in his tank, or Thane has not been recruited) then the mission of the next character present will unlock instead. Speaking with Kelly Chambers between missions will let you know which squad members you can talk to for new loyalty missions.

Gaining the loyalty of a squad member unlocks their "Bonus Power" for them to use. The first time a Bonus Power is ever unlocked, it is also added to the Advanced Training list for Shepard.

Each squad mate also has one Normandy Upgrade or research project to unlock in the research lab. Once Shepard has access to the research lab, these can be unlocked, even during Act 1, by talking to the squad members before they offer their loyalty missions and selecting the "[NORMANDY UPGRADES]" option under the Investigate heading; otherwise it unlocks automatically as each loyalty mission is complete.

Miranda: The Prodigal

Jacob: The Gift of Greatness

Jack: Subject Zero

Mordin: Old Blood

Grunt: Rite of Passage

Garrus: Eye for an Eye

Samara: The Ardat-Yakshi

Tali: Treason

Thane: Sins of the Father

Legion: A House Divided

Act 2 DLC[edit | edit source]

The following DLC becomes available for the first time when Act 2 begins. These are both large, substantial, and challenging undertakings, and offer significant rewards.

Lair of the Shadow Broker

Arrival

Act 2 Progression Missions[edit | edit source]

Several key progression missions take place during the course of Act 2. Only the Reaper IFF mission may be done whenever you're ready; the other two trigger automatically.

Collector Ship - triggers a few missions after the events on Horizon. See the acquisition section on the mission page for specifics.

Reaper IFF - choose anytime after the Collector Ship mission. However, once completed, a mission countdown activates, with the possibility of significant plot consequences if the player delays much before proceeding through the Omega 4 Relay and beginning Act 3.

Await IFF Installation - triggers aboard the Normandy immediately after obtaining the IFF from the Derelict Reaper.

Act 3[edit | edit source]

Act 3, also known as the Suicide Mission, begins when the Normandy enters the Omega 4 Relay, which can be done freely any time after Await IFF Installation is complete. At this point the mission sequence is locked, and the game proceeds through to the Epilogue without any intervening break for Shepard to use the Galaxy Map, complete assignments, research upgrades, etc. If Shepard survives the Suicide Mission, however, additional missions and assignments (DLC or left over from Acts 1 and 2) can then be completed.

Before entering the Omega 4 Relay and thus launching Act 3, you will want to upgrade your ship. The important upgrades are the shields, the armor, and the cannon. Tali, Jacob, and Garrus, respectively, provide these upgrades. For each of these you do not upgrade, you will later lose one team member. Upgrades will also increase the Normandy's value as a War Asset in Mass Effect 3.

The following list shows, in order of preference, which crew member will die if you haven't upgraded a particular part:

  • Heavy Ship Armor: Jack
  • Multicore Shielding: Kasumi, Legion, Tali, Thane, Garrus, Zaeed, Grunt
  • Thanix Cannon: Thane, Garrus, Zaeed, Grunt, Jack, Samara/Morinth

Note: This tier is sorted by the characters' order of dying in descending order. Squad members on the "Multicore Shielding" list will not die if they are in your party when you fight the Oculus. Bringing Jack to fight the Oculus will not protect her if you do not have Heavy Ship Armor, nor will bringing anyone on the "Thanix Cannon" list save them from their fate.

Act 3 Progression[edit | edit source]

The Normandy Attacked - Defend the Normandy from the Oculus.

Collector Base: Infiltration - Help your tech specialist through the ventilation shaft.

Collector Base: The Long Walk - Your biotic specialist escorts you through the Seeker Swarms.

Collector Base: Final Battle - Face the truth behind the abductions and make your decisions.

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