Mass Effect 2: Tali: Treason - walkthrough Mass Effect 2 guide, walkthrough

Last update: 02 June 2021

Description: This quest should appear in your journal after completing several missions following your trip to the Horizon and naturally you must pay Tali a visit to learn more about her problem. Tali can be found in the machine room on the fourth deck of the Normandy and during the conversation you should agree to provide help in clearing her name. This mission can be continued by opening the galaxy map and plotting a course for the Valhallan Threshold. After you've made your way to Raheel-Leyya system confirm that you want to dock on one of the ships of the Migrant Fleet.

As soon as you've boarded one of the ships of the [Migrant fleet] you'll have to talk to Captain Kar'Dann and then you'll be allowed to start exploring the vessel. Head forward and it shouldn't take long until you'll have a chance to meet Shala'Raan. This is going to be a longer conversation and it will be automatically followed by a hearing.

Notice that you'll be allowed to choose a special dialogue option (paragon or renegade) during the hearing, however it won't affect the conversation in any major way. The hearing has to end with your team being sent on a mission to destroy the geth on board of a research vessel named Alarei.

You should spend some talking to other quarians after the hearing has ended. You can find Veetor'Nara, Admiral Xen and Kal'Reegar (assuming he's still alive) in the northern section of the hall (first screenshot) and Shala'Raan (this is going to be your second conversation with her), Admiral Gerrel and Admiral Goris in the southern section of the hall. Don't forget to be thorough by asking a lot of additional questions.

This mission can be continued by choosing a passageway located in the southern section of the main hall (first screenshot). Keep heading forward and you'll soon reach the exit where you'll have to talk to a Shuttle guard. Confirm that you want to use the shuttle and wait until you're transported to the research ship.

Save your current game and then head forward. The first serious battle will take place in the next room. I would recommend staying somewhere near the entrance, waiting for geth to show up and eliminating them at close range. Don't forget to be on a look out for hunters, because their camouflage ability will make them harder to spot. Use tech powers to your advantage, especially overload which will be useful at taking down stronger enemies.

After you've eliminated all the geth you should spend some time looking around to find a med kit and power cells. You can also hack into two laptops, gathering 1500 and 1800 credits. Finish off by listening to a recording from a console found in the corner of the room.

You may continue exploring the research ship by choosing the only available passageway. You'll soon get to several doors (first screenshot) and you should start by checking a room found to your left. You'll find a med kit there, as well as a new terminal (4200 credits) and a research drone (you can talk about the drone with Tali).

Exit the room and continue heading forward. Notice that you'll have a chance to hack into a nearby computer terminal to acquire a plan for a new research project. There's also a second terminal in the area (second screenshot), however this one contains only a recording. Save your game before moving any further.

You'll have to be ready, because as soon as you've opened the door you're going to be attacked by several hunters. Immediately ask your team members to take cover and then get rid of all the geth. Keep fighting until you've won and then check the right side of the room to find two laptops with 1800 and 2100 credits.

You may proceed towards the passageway where all the machines were showing up. You'll find yet another terminal here (first screenshot), as well as a safe (4200 credits). Use the stairs to get to the upper level and get ready to take part in a new battle. Like always, you should begin by finding a good cover for you and for the rest of your team.

You shouldn't be surprised to hear that aside from standard geth units you'll also be going against new hunters here and you'll have to prevent them from moving too close to your team. Check the area after the battle to find a med kit and a container with 2000 units of palladium.

You should also explore the next room of the ship, because you'll come across a safe and opening it will grant you with 3000 credits. Check one of the wall consoles to initiate a new conversation with Tali while you're there. Exit the room and order your followers to take cover behind a balustrade (second screenshot), because new geth units will arrive very soon.

During the first phase of this battle you should be able to use the fact that you're occupying an upper balcony, making it easier to defeat most of the geth. Later in the battle it will get tougher and you'll have to focus on defending the stairs (second screenshot), preventing the machines from reaching the balcony section.

Be careful, because a single geth may surprise you near the end of the battle - the machine will appear in the left window on the same level (first screenshot) and you'll have to destroy it before it has a chance to surprise your team. Head down to a lower level. Look around here to find a med kit, two laptops (2400 and 1800 credits) and a computer terminal with a new recording.

Proceed towards the left corridor. You'll soon encounter a critically injured quarian and you'll discover that it's Tali's father. You'll have a chance to cheer up your teammate using a special paragon interrupt (first screenshot) and after Tali's father has passed away check the room found to your left (second screenshot). You can hack into two safes here (1500 and 2700 credits), pick up a med kit and collect power cells.

SAVE your game, because you're about to take part in the main boss battle. Use the stairs and once you're inside a new room don't forget to take a model of the ship to add it to your collection (first screenshot). You can also collect 3000 credits from a terminal and then you should consider choosing a heavy weapon from your arsenal.

A geth prime is the main boss of this battle and he'll be protected by several geth hunters and soldiers. The biggest problem about this fight is the size of the room. You'll have to keep moving and use a gun good for close quarters combat. Keep healing your teammates if you notice them dying. Destroying the prime will only be possible if you destroy its shields first and then its armor.

Keep attacking the geth units until they're all eliminated and then approach a large quarian console (first screenshot). Interacting with the console will uncover the truth about the situation here and you'll be allowed to choose what to do with the found data. Leave this ship to return to the main quarian vessel. You'll now have to return to the council chamber (large area where you've already taken part in a hearing). I would recommend that you save your game before opening the door leading to that area (second screenshot), because you'll soon have to make a very important decision.

This quest has four different endings. If you want to unlock the best possible ending you'll have to choose a special dialogue option (paragon or renegade) during the upcoming debriefing. Sadly, it will only be possible if you've suffieciently developed one of your karma bars (paragon or renegade). If you can't use a special dialogue option you'll have to choose between hiding the truth (Tali will be banished from the fleet), using the crowd to your advantage (a good choice for Tali) and telling the truth (Tali will be banished and she'll be furious at Shepard). You can now finish the quest right away by pressing and holding the F key or you can talk to some of the quarians again to unlock new dialogue options.