Mass Effect 3: Priority, Rannoch - walkthrough Mass Effect 3 guide, walkthrough

Last update: 13 October 2022

On this page of the Mass Effect 3 game guide you will find a description of the main quest Priority - Rannoch. This walkthrough explains how to find the Reaper base on Rannoch, how to defeat the three behemoths, how to properly summon a raid, how to defeat the Reaper boss, and what important choice Shepard has to make when talking to Tali and Legion/Geth VI.

• Getting to the Reaper base on Rannoch
• Exploration of the geth base
• Eliminating Geth Forces
• Boss fight - Reaper
• Meeting with Tali and Legion/Geth VI - an important choice

Getting to the Reaper base on Rannoch

Received from: Quarian admirals [Normandy SR-2: Combat Information Center]

Unlocked by: Received automatically after completing Priority: Geth Dreadnought, however you won't be allowed to start the new mission until you've completed the quest about saving the quarian admiral (Rannoch: Admiral Koris) or the quest about neutralizing the geth squadrons (Rannoch: Geth Fighter Squadrons).

Make sure you've fulfilled the requirements for this mission, so you must complete either the quest about admiral Koris or the quest about the geth squadrons. Once you've done that wait until you've returned to the Normandy and the game should automatically trigger a cut-scene showing a meeting involving the main character, quarian admirals (+Tali if she's not an admiral) and Legion/Geth VI.

During the meeting you'll find out that the Reaper base has been located on the surface of the planet Rannoch. It's important to know that you don't have to make a final decision right now whether you plan on helping the geth or not, however the subject will be mentioned and you'll have to show your "unofficial" support for one of the sides of the conflict.

Open the galaxy map and travel to the Perseus Veil. Once you're there (Tikkun system), fly to the planet Rannoch.

Tali must take part in this mission, so choose wisely who should accompany her and Shepard in order to ensure that the entire team is versatile and will be able to deal with various threats. Wait until you're transported to [Rannoch: Geth Base], listening to conversations with Tali and Legion/Geth VI in the meantime.

Exploration of the geth base

As soon as the main part of the mission has started you'll be forced to attack the first group of geth units. Order your team to take cover behind nearby objects and then begin eliminating the geth, preventing them at the same time from moving too close. You can also consider flanking the geth, however the battle itself isn't too hard (you won't encounter any elite geth units here) so it's not mandatory.

Once you've secured this entire area take a look around to find a weapon mod [SMG High Caliber Barrel].

Locate the metal objects and climb on them in order to reach two ladders seen in the distance. I would recommend choosing the ladder located to your right, because once you're on an upper balcony you'll have better choices for cover and therefore won't have to worry about defending against the geth attacks.

Watch out for rocket troopers and their ranged attacks mostly from the upper balconies. Rely on Tali's power as much as you can. You should also be ready to defeat an additional geth after making a few steps forward. Keep fighting until you've won and then search the area to find a weapon mod [Mod SMG High Caliber Barrel] and an armor fragment [Kassa Fabrication Gauntlets].

You may now proceed towards a new ladder. Start off by climbing to an upper balcony and then use the nearby balustrades to take cover along with the rest of your team. Attack the geth seen on the lower level, however you must also watch out for machines which will appear in front of you, on the same level you currently occupy. You should know that you'll be allowed to flank that second group by choosing the passageway located to your left. It doesn't matter how you'll act during this battle, because the objective stays the same - you must eliminate all geth opposition. Once it's safe go down to the lower level, because this is the only way to reach a corridor leading to the main part of the base.

Take a look around to find the Reaper technology [10000 credits] and then proceed to the next part of the complex. Soon after witnessing a blast shield closing down turn left in order to find a weapon mod [SMG Ultralight Materials].

Once you have the weapon upgrade choose the unexplored right passageway. Order your team to take cover and then attack the geth seen in the distance. Don't perform any risky actions and try to prevent the machines from moving closer if you can. You should also consider throwing grenades each time you notice several geth standing close to each other.

Deal with all the geth stationed nearby and once it's safe check the area to your right in order to locate a new weapon mod [Assault Rifle Stability Damper]. Continue your journey, eliminating all the geth you encounter and eventually finding a door. Look around to find an excellent shotgun [Geth Plasma Shotgun] and some data [5000 credits].

Open the door and proceed to the next section, finding more data [10000 credits] and a med-kit [100 EXP] along the way. Save your progress before opening a second door leading to a much larger area of the base.

As soon as you've entered a new area of the map you'll find yourself under heavy fire from the geth, so it's important to quickly find cover for Shepard and the rest of the team. Ignore the area to your right, because enemy units can't get to you from there. Focus on the left passageway instead. Depending on your favorite style of play you can wait for the geth to come to you or you can advance aggressively, trying to secure this area in a shorter amount of time. Either way, you must get rid of all geth.

Locate a med-kit [100 EXP] and memorize the locations of nearby ammo stashes, because you might need to quickly use the supplies later on in this mission.

Once you feel you're ready to proceed to the next part of the mission interact with an override console. Quickly position your team near the left corridor, because the geth will start coming out of one of the side rooms. Watch out mostly for geth rocket troopers and for pyro geths. You should also consider throwing several grenades at the beginning of the battle, because that's when all the machines will be standing very close to each other. Continue fighting until you've successfully defeated all geth units.

Eliminating Geth Forces

You must now repeat all the actions with the second override console. Doing this will activate a small lift seen in the distance. Don't go towards the lift right away, because new geth will arrive in it, including a geth prime. Focus on keeping the prime at a safe distance and don't forget that Tali's tech powers can make a real difference when it comes to weakening or sabotaging the large machine. Once you've defeated all enemy units collect ammunition and SAVE your game. Make sure you're ready before interacting with the lift's control panel.

Once you've reached the new level of the base the game will start the most difficult battle of this mission during which you'll be going against THREE geth primes. Thankfully you're not left without help, because you'll find unique geth weapons [Geth Spitfire] in the area which you may already know from the Rannoch: Admiral Koris main quest. One of the weapons can be found in front of the elevator (screen above) and two additional spitfires are hidden to the left and to the right. Pick up the geth spitfire, find a good cover and start attacking one of the geth primes. The good news is that the weapon is very strong, so you won't even have to ask Tali and another team member for help.

Keep using the spitfire until you've defeated the first geth prime. Heal your allies if they were injured and change your location if you see that other geth primes are heading your way. This is also a good moment to pick up a brand new spitfire, especially since you won't need these weapons later in the mission.

Begin attacking two remaining geth primes and make sure that you're focused on a single target. It's also important to heal Shepard immediately after receiving injuries, so you won't die suddenly. You can ignore small geth turrets flying close to geth primes, because each turret will be destroyed along with the prime that has created it.

Boss fight - Reaper

Continue fighting until all three geth primes have been destroyed. There aren't any interesting items in this area, so save your current progress and start moving towards a small platform seen in the distance. Once you're there Shepard will automatically choose a unique weapon [Laser designator] from the inventory in order to assist in calling in an airstrike. Look down, aim at the Reaper and hold the left mouse button until the aiming process has ended.

Watch an explosion and once you've regained control over Shepard start moving towards the shuttle. You won't have to sprint here and you also won't have to avoid the Reaper's legs as during the mission on Tuchanka. The shuttle escape is also very easy. Just keep using the stationary turret without having to aim at any specific areas of the Reaper's armor.

The game will soon trigger another cut-scene and as soon as it has ended you'll be forced to take part in a duel with the Reaper.

You will be performing two types of actions alternately during this "boss" battle and they're both not that difficult as you could have imagined. The first action is to continue using the laser designator to target the Reaper for airstrike and this is achieved by holding the left mouse button. You can start (or resume) the aiming process after the Reaper has begun to load its primary weapon (screen above).

The moment you see that the Reaper is ready to fire its main gun you'll have to do the second thing. Stop aiming and run either to your left or right. I wouldn't recommend trying to perform a simple dodge maneuver, because that may not be enough. The whole point of running is to move away from the area that was targeted by the Reaper. As soon as you're in the clear start using the designator again (action 1) by holding the left mouse button. An important thing to know is that the aiming process doesn't start from the beginning, but it's resumed, so you don't lose your current progress.

Each time you've managed to complete the aiming process you'll call an airstrike. This means the Reaper will suffer damage and you'll advance to the next stage. The battle can be won after the boss has been targeted several times. The final targeting process is slightly different, because the game will zoom in the camera and initiate slow-motion (screen above). DON'T interrupt the aiming process, because you'll be allowed to finish it before the Reaper has a chance to fire the main weapon.

You will now watch a very interesting cut-scene showing the entire fleet attacking and defeating the Reaper.

You'll also have a chance to talk to the Reaper and depending on your choice you can choose a neutral dialogue option (middle left), a paragon dialogue option (upper right) or a renegade dialogue option (lower right). If you didn't choose the neutral question you will also be granted a chance to activate a paragon interrupt (right mouse button) or a renegade interrupt (light mouse button). The choices you make here won't influence the rest of the quest in any major way. The next conversation (with Tali and Legion/Geth VI) is the one you should be interested in, because that's when you'll have to make the most important decision.

Meeting with Tali and Legion/Geth VI - an important choice

Start off by listening to the initial statements made by both parties. Legion/Geth VI will want your approval to send the Reaper code to all geth, "awakening" them and therefore granting them with an intelligence and will to join the war with the Reapers. Tali will be representing the interests of quarians and will be against geth plans, seeing them as a major threat to the quarian race and to all other organic life in the galaxy.

Here are three possible ways of resolving this conflict:

1. Variant 1 - Siding with the geth. If you want to support the geth in their wishes to become intelligent, then you must choose the upper right dialogue option. This will allow Legion/Geth VI to send the Reaper code to all geth. The machines will turn on the quarians, defeating their fleet in a massive battle near Rannoch. That's not all, because Tali will be devastated by the fall of her race and she will try to commit suicide. Sadly even if you manage to trigger a paragon interrupt (right mouse button) you won't be able to save her and this means you'll lose her forever. To summarize, choosing this option will allow you to gain geth as allies, however you will lose all quarian war assets and you'll have one team member less to choose from.
2. Variant 2 - Siding with the quarians. If you want to support the quarians in their concerns about turning geth into intelligent beings, then you must choose the lower right dialogue option. This will allow you to stop Legion/Geth VI from sending the Reaper code to all geth. The quarians will take initiative, defeating the geth fleet in a massive battle near Rannoch. That's not all, because Legion/Geth VI will respond to your choice in hostility and you can either use the renegade interrupt (left mouse button) to destroy it yourself or wait for Tali to do the killing for you. To summarize, choosing this option will allow you to gain quarians as allies, however you will lose all geth war assets.
3. Variant 3 - Convincing the geth and the quarians to work together. This is by far the best possible outcome you can achieve, because you'll gain both the geth and the quarian war assets. If you want to convince both parties to form an alliance, then you must choose the special paragon or special renegade dialogue option. Sadly, both of these dialogues appear on the dialogue wheel only if you've fulfilled strict requirements.

Here's a list of factors that may increase the chances of this solution becoming available:

1. playing as a character with a sufficient reputation,
2. rescuing admiral Koris (Rannoch: Admiral Koris main quest),
3. Tali being promoted to admiral status (Mass Effect 2),
4. saving the Legion from destruction (Mass Effect 2),
5. performing Legion's personal quest and destroying the heretics base (Mass Effect 2),
6. solving the conflict situation between Tali and Legion at the end of Legion's personal quest (Mass Effect 2).

To summarize, choosing variant 3 will allow you to gain assets from the geth and from the quarians (you won't lose any assets).

After you've made your choices you'll watch several additional cut-scenes. The most important cut-scene will be a conversation with an asari councillor. She will ask Shepard to meet her on the Citadel and this conversation will also unlock a new main quest - Priority: The Citadel #3. Consider talking to admiral Hackett as well before leaving Normandy's war room.

Prizes for completing the mission:

1. Mission unlocked: Priority: The Citadel #3
2. [25000 credits]
3. War asset [Geth Corps] (only if the geth fleet wasn't destroyed)
4. War asset [Geth Fleet] (only if the geth fleet wasn't destroyed)
5. War asset [Admiral Daro'Xen] (only if the quarian fleet wasn't destroyed)
6. War asset [Quarian Civilian Fleet] (only if the quarian fleet wasn't destroyed)
7. War asset [Quarian Heavy Fleet] (only if the quarian fleet wasn't destroyed)
8. War asset [Quarian Patrol Fleet] (only if the quarian fleet wasn't destroyed)