Priority: Mars is a Mission in Mass Effect 3. Missions serve as the main quests of the game. Completing Missions progresses the story and is the key to beating the campaign.



General Information

Previous: Prologue: Earth

Next: Prority: The Citadel I

Locations: Mars


Video Walkthrough

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NPCs in the area



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Equipment & Upgrades

Key Items

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Priority: Mars Full Walkthrough

Getting Started

This Mission is automatically acquired after the conclusion of Prologue: Earth.

In the opening cutscene, you will get your first Interrupt opportunity during the conversation with James Vega. Interrupts are a conversation mechanic that tie into the Morality System. Certain scenes will prompt either a Paragon or Renegade interrupt, or a choice between the two depending on dialogue choices made. Interrupts opportunities are signaled by the Paragon or Renegade symbols on the bottom left or right corner of the screen, along with a button prompt to execute the Interrupt. Note that Interrupt opportunities are only available for a few seconds, necessitating a quick response. Otherwise, the conversation defaults to a neutral state. While Interrupts are completely optional, they typically award a significant boost to either side of the morality scale and often steer the conversation or scene into interesting outcomes.

Shepard will begin this mission equipped with a different weapon depending on the class chosen:

Any weapon you do not start with can be found as loot during the mission. Note that Power recharge speed is affected by your carry weight and using heavier weapons may prove detrimental to Power-focused classes.


After the cutscene, you disembark from your shuttle onto the Martian surface. You are joined by James and either Ashley or Kaidan. Follow the on-screen prompt to level up your squad and then head for the path to the right of the solar panels as you listen to banter from your squad. At the end of the path, there is an opening between the railings you can jump down from. If you do not already have one, you can pick up the M-92 Mantis Sniper Rifle on the ground here.

Head down the path on the left to find a group of Cerberus Assault Troopers executing civilians. These are standard infantrymen equipped with SMGs and shock batons. They can use grenades and they lack shields, making them easy to stagger with any attack. This first group you encounter are all within a few steps of each other, oblivious to your presence until you engage them or get too close. You can use James' Frag Grenade power to take them all out in one fell swoop. Past the first group, you will be ambushed by more Assault Troopers coming in from behind the parked vehicles. After defeating every single trooper, head for the facility and activate the elevator to trigger a lengthy cutscene with several dialogue opportunities for morality points. The group is reacquainted with Dr. Liara T'Soni who joins your squad as James is sent back to the shuttle to cover the exits in case Cerberus beats the group to the archives.

You regain control of Shepard as you are attacked by more Cerberus troopers. Liara is excellent at flushing opponents out of cover with her Singularity so take advantage of her abilities. After the battle, you can pick up the Med Kit to the right of the room. Head for the lift which you immediately find out has been sabotaged. Make your way around the left side of the room to find a panel that activates the vehicle lift next to it. Head up the incline to the left of the lift, up the crates and across the raised vehicle to get to the upper platform. Make your way to the door at the end of the path and get into cover.

Follow the prompt teaching you how to perform a quick-kill from cover, taking out the Cerberus trooper and then defeat the rest of the enemies in the room. Enter the next hallway where you will find a control room around the corner. Right in front of the door is a container with the Ariake Technologies Gauntlets. Further in, you will find a Med Kit on the ground and the M-4 Shuriken SMG nearby. Use the security console on the right to open the airlocks to the outside. Note that there is a small lounge area outside the control room where you can examine a Datapad from the seats. Head out the airlocks.

You end up outdoors. Head down the ladder to the left and you will see two tram carts in the distance with Alliance and Cerberus troops firing at each other. Follow the walkway to the left to find another ladder heading up. Pick up the container before heading up the ladder for a Kassa Fabrication Chestplate. Up above, hop across the gap and through the opened airlock to the left leading to a darkened corridor with a few dead bodies around. Continue along the walkway and turn right when possible. There is another Datapad on the floor you can examine before heading down to the Cafeteria area. While walking down the second set of steps, you see the shutters opening up as your squad shuts off their flashlights while a squad of Cerberus troopers discuss searching the cafeteria. You can move towards the windows as the troopers are talking to perform a quick-kill from cover or simply take them all out by shooting through the windows. Before hopping through the windows, check the right side of the cafeteria for an SMG Scope upgrade. Past the windows and to the right is a control booth with a Medical Station. Activate the environmental controls panel to unlock the doors to the labs and tram station, triggering a cutscene that reveals Dr. Eva as being responsible for venting the air out of the facility and killing the employees within.

Head through the door and you will find a weapon bench in the corner to the right in the next room. You can change your weapon loadout here, as well as attach any upgrades you've found. There is also an SMG Ultralight Materials upgrade behind the junk pile nearby and a Datapad at the bottom of the stairs. Head up the steps and through the door for your first encounter with Cerberus Centurions and Guardians. Centurions are elite troopers armed with assault rifles, possessing moderate health and shields. They can deploy smoke grenades that obscure your vision and prevent locking onto targets with your Powers, as well as making it more difficult to see incoming grenades and other explosive effects. Guardians are troopers carrying large physical shields that grant them strong defensive capabilities. They also wield shotgun pistols that are deadly at close range. Their shields can be circumvented by shooting their hands or feet, throwing grenades to their side or behind them or using Powers that go through shields and barriers. Additionally, the shield has a tiny opening near the top for the Guardians to see through and a well-placed shot with an accurate weapon can deal massive damage or outright kill them.

Defeat the first wave and move along the two hallways. There is a Datapad in the middle section between the two hallways. Turn left into the third and fourth hallways, fighting through more waves of enemies to fight. They will eventually fall back and call for a retreat into the tram station. Continue on until you come across a lab that's being decontaminated. There is a console to the right of the door which will allow you to deactivate the decontamination protocol. Use it when the orange barrier is wide enough to pass through. Inside the room, you can pick up the Shotgun High Caliber and Sniper Rifle Extended Barrel upgrades, as well as a Med Kit and Datapad. After collecting everything, continue past the door in the back.

Through the door, take the left corridor and make a right when you can. You can find an M-23 Katana Shotgun next to the corpse on the right, opposite the door. Opening the door, you are attacked by an automated turret. You cannot destroy it and it will make quick work of you if you remain out of cover. Follow the on-screen prompts to skirt around from cover to cover in between the turret's bursts until you eventually get out of its line of sight, causing it to deactivate automatically. Head through the door after the turret deactivates and kill the Cerberus troops around the corner. There is a Med Kit, Datapad and a Sniper Rifle Concentration Mod to be found in the control booth section. Go to the main terminal and activate the auto-turret controls, triggering a cutscene and subsequent dialogue with Kaidan or Ashley.

When the cutscene ends, you are given a brief tutorial on squad controls. Send your squadmates to the marker and await the tram to ambush the Cerberus troops. You can head back up to the control booth to refill ammo if needed. Step onto the tram and activate the controls to begin the next sequence. Your tram is stopped immediately by a explosives planted along the railway as another tram filled with Cerberus troops approaches yours. Defeat the enemies and hop onto their tram as it closes in and activate the controls.

Once you get to the station, you will be thrust into another large fight with the first wave composed of a lot of Centurions and Assault Troopers. Make use of the pockets of cover by the walls and the crates in the middle but watch out for the smoke grenades. Alternatively, you can prop your squadmates by the walls or crates while you hang back in the tram, picking off troops one by one in relative safety. The second wave of enemies will include Guardians but the way the room is set up should allow you to easily throw grenades and powers behind or to the side of their shields. When you've cleared the troops, head for the back of the platform past the control booth and pick up the Shotgun Shredder Mod on the back wall to the right, and an M-15 Vindicator Assault Rifle on the left. There is also a Med Kit in the control booth. The door in the back leads to the archives and the final stretch of the mission. Once you're prepped, open the door for a cutscene with the Illusive Man.

Near the end of the cutscene, it is revealed that Dr. Eva had been sabotaging the Prothean data and promptly knocks either Ashley or Kaidan down when she is discovered, beginning a chase sequence. For this final objective, simply chase Dr. Eva down the facility while taking cover when she throws longer barrages of attacks at you. Do not bother with attacking her as she has an exceptionally high shield recharge rate, and will instantly regenerate even if you do manage to break them. You need to keep within 40m of Dr. Eva or the mission will fail. Near the middle of the sequence, some Cerberus troops will arrive in a shuttle. You can simply ignore them or throw them out of the shuttle to their deaths with Liara's Singularity. At the end of the chase, James will come crashing the Normandy's shuttle into Eva's shuttle, preventing her escape. It is soon revealed that Dr. Eva is not human as she emerges from the fiery wreckage, heavily injuring either Ashley or Kaidan. She begins running at Shepard and you will need to shoot her down with your pistol. Aim for the head for best results. The mission ends with the capture of Dr. Eva's body as Shepard tends to his injured companion.


Next Mission:  Priority: The Citadel I


Trivia & Notes

  • Trivia and notes go here




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