Priority: Cerberus Headquarters | Mass Effect 3 Wiki

Priority: Cerberus Headquarters Full Walkthrough

Getting Started

This mission is acquired automatically after the conclusion of Priority: Horizon.

This mission will have EDI join you as a mandatory party member, leaving you with only one other slot to pick a squadmate. Pick wisely as you will be faced with the brunt of the Cerberus forces. In particular, there will be an abundance of Phantoms. It is highly recommended you bring someone with good crowd control and can compliment EDI's anti-shield capabilities.

Warning: This is the point of no return for most activities in the game. Beginning this mission will lock you out of all Side Missions and other interactions outside of the Normandy. If you are interested in completing them at all, do them now as you won't get another chance afterwards.

When ready, head for Cronos Station in the Anadius system. Once you choose to dock, you will have a conversation with Admiral Hackett via comms. He informs you that the Crucible is ready except for the Catalyst and launching an assault on the Cerberus base will likely cause the Reapers to take notice, necessitating that you see the plan to the very end once you begin. This will be your final chance to back out if you still wish to complete other activities.

Before actually beginning the mission, another forest dream sequence will occur. This time with another Shepard catching the child in an embrace before they burst into flame. 

Walkthrough

The mission opens with the squad coming to a hard landing into the station's docking bay where you are immediately faced with Assault Troopers, Centurions and an Atlas Mech. Beware of the constant deployment of smoke grenades and reposition as necessary. Watch out for the Nemesis who roams the upper platforms at the edges of the room. Once you defeat the enemies, EDI will inform you that the hangar bay is about to be vented and asks you to find an active console to stop the process. Quickly run to the left of the room and find a ladder leading up to the upper platform where the Nemesis was. Turn right and go through the door to find a console on the right. Note that taking too long with this will cause the mission to fail as the venting process kills your team.

After the scene, more enemies will swarm in from the other end of the room opposite where you came in. Defeat them and follow the corner to the other side's upper platform and control room. More Cerberus forces will show up from control room as you get close. Be aware of the Nemesis who is probably sniping from the far end of the walkway. Once you make it to the room, activate the Rotation Controls terminal which rotates the fighter ship in the hangar towards the main blast door. Pick up the Med Kit in the small pocket opposite the controls then head out the back door of the room. Before going down the ladder back to the main hangar floor, go through the door ahead and pick up the PDA for 5,000 Credits. Head back out and down the ladder, then launch the fighter using the console directly to your right. It destroys the hangar door but an Atlas Mech appears from the wreckage. There is an unmanned Atlas Mech in a narrow pocket in the wall on other side of the hangar door. You can ride one of these to even the odds in the fight. There will be other infantry attempting to take the other mech. If you can prevent them from reaching it, you won't have to deal with an additional mech. Head for the door's wreckage and pick up the M-37 Falcon Assault Rifle on the ground to the left. Have EDI bypass the other door to the very left and then head down the ladder to the sub level.

Get into cover and eliminate all hostiles in the area. There is a Nemesis propped way in the back of the room. After taking her out, another set of troopers and Centurions will drop in from the ladder at the back. Once the coast is clear, head for the wall in the far back opposite the ladder for a Med Kit and a terminal you can salvage for 5,000 Credits. Head up the ladder and EDI will begin another bypass for the door in the back. She will point you towards the terminal in the corner containing details regarding Project Lazarus, the Cerberus program that reconstructed and revived Shepard. There are several entries that you can view for more insight into the project as well as other projects Cerberus initiated. Once you close the log, EDI will have completed the bypass. Pick up the Serrice Council Greaves right behind you before heading out.

Follow the corridor past the door and turn right through the section that isn't engulfed in flames. Drop down into the hole ahead and prepare for battle. Defeat the troopers and then carefully turn the corner to see a group of Combat Engineers who have propped up their Turrets and are being supported by Shield Pylons. Bombard them with Powers where you can. Sabotage the turrets if you have the Power equipped and take your time if it proves too difficult. At the end of the corridor is another ladder leading up to another room with a similar console to the last. Activate the console if you wish to learn about the Cerberus projects. This one concerns EDI. Head for the adjacent room and EDI will begin bypassing the door. In the meantime, pick up the PDA on the right worth 5,000 Credits and a Med Kit on the wall in the far left.

In the next hallway, there is a glowing blue hole in the left wall where you need to go to. Before heading down, continue on to the end of the hallway and enter the door on the right. You can find a Med Kit and a Delumcore Overlay along the tight space. There should be another door here which leads into a room with another of those consoles, this time focusing on info regarding Kai Leng. When you're done, backtrack to the hallway and jump down the glowing blue hole.

The hole leads to a large chamber where the remains of a Human-based Proto-Reaper is being held. This should be a familiar sight if you've completed the previous game. Make your way across and up the walkway encircling the Proto-Reaper corpse. You will be faced with plenty of Phantoms and Nemeses as you proceed. Look out for Shield Pylons supporting the enemy troops and deal with them accordingly. The path here will be fairly linear but you will be faced with opponents at every corner so stay vigilant. Depending on previous choices you've made, you may encounter former friends as enemies here. If you did not complete Grissom Academy: Emergency Evacuation, an indoctrinated Jack will appear as you approach the ladder at the end of the area, behaving identically to a Phantom. If you've sold Legion to Cerberus in Mass Effect 2, it will appear as Legion Assassin here. The Legion Assassin behaves like a Nemesis and is similarly equipped with a Sniper Rifle. If encountered, you will be forced to kill these foes in order to proceed. After climbing the final ladder, walk in the opposite direction before going through the door to pick up a PDA worth 5,000 Credits and a Med Kit.

Through the door, you will be in a large room with several terminals. One of these will be the final console containing info on Cerberus Projects. This one concerns the Cerberus Implants. There is also a Med Kit on the ground nearby and another PDA worth 5,000 Credits. Through the door is a long ramp leading to the Illusive Man's inner sanctum. As per his track record, the Illusive Man appears merely in hologram form and goes on his usual tirade about controlling the Reapers. You will have a few dialogue options here but they will all lead to the Illusive Man cutting off communications. Edi then finds and recovers Vendetta, the Prothean VI from the Asari temple on  Thessia who reveals the Catalyst to be The Citadel itself. The VI then informs you that the Illusive Man had warned the Reapers of your plans and they have moved the Citadel to Earth. Shepard then decides to move the Crucible to Earth, asking EDI to contact Admiral Hackett when an explosion goes off in the room. Kai Leng appears once more and the final confrontation with him begins.

Immediately after the cutsccene, he will be within melee range. Move away quickly or stagger him with a melee attack. As with the previous encounter, keep your distance and chip away at his shields. If he manages to get close, he will perform a special melee attack that you can block by mashing the melee button. Otherwise, it will kill you instantly. Kai Leng will periodically destroy portions of the floor when he recharges his shields, creating some usable cover but it's really not necessary to use them. Eventually, he will begin summoning Troopers, Phantoms and Nemeses to support him. Prioritize the Phantoms and Nemeses before going back to Kai Lang as they will be the biggest threats while active. Once you finally defeat him, Shepard will return to the Illusive Man's console and Kai Leng will get back up and attempt a last-ditch effort to kill the commander. There will be a Renegade Interrupt prompt as the assassin sneaks up on you. Ignoring the Interrupt will cause Shepard to dodge while taking it will cause him to block and shatter the blade. In either case, he will follow up with a stab with the Omni-Tool, finally putting an end to Kai Leng.

The mission comes to a close with a final conversation with Vendetta. There will be a Renegade Interrupt opportunity here, but if you wait, you can perform a Paragon Interrupt instead. This has no bearing on the story and is simply for extra morality points. Back on the Normandy, David Anderson confirms that the Citadel is now in Earth's orbit and you unlock the final mission of the game, Priority: Earth. 

Trivia & Notes

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