Now that you’ve completed one of the two previous side-missions, you can move on to the next story mission. Shepard has been given a laser designator to call down an orbital strike on the Geth base on Rannoch. In order to accurately paint the target, Shepard must first infiltrate the Geth fortifications. Tali’s presence is required, so make sure the other squadmate you bring along will benefit you in battling Geth forces.
After a brief cutscene that takes place when you land, you’re thrown into action just outside the Geth stronghold. Progress down the hill towards the open door at the bottom, taking down the Geth that stand in your way. Once you reach the bottom, the door will slam shut, and more Geth Troopers will drop in to attack. After killing them, head towards the door. On the right, you’ll find the SMG High Caliber Barrel III. Grab that, and then proceed back out into the open area. Look to your left and you’ll see a series of platforms and ladders to climb. Once you get to the ladders, you have the choice of going either left or right. It doesn’t matter which way you choose as you’ll have to fight the same few Geth forces no matter what.
Climb up and keep taking down the Geth as you move forward. When you reach the final platform area, you’ll spot a ladder on the left that will take you up to the next section. Before heading up there, be sure to grab the Kassa Fabrication Gauntlets beneath it, and the Assault Rifle Piercing Mod III located where the Geth Rocket Troops were hidden behind cover. After getting those items, climb up the ladder, and make your way up the pipes in front of you.
In this next section, you can choose to maintain the high ground against the Geth soldiers, or drop down onto the walkway below to fight them. Geth Rocket Troopers will drop in from above, so you may find it advantageous to stick to the upper catwalk during this next firefight. After every Geth has been eliminated, head into the door at the far end of the walkway on the right. Inside there is some Reaper Tech to salvage on a terminal. Make sure to grab it before heading up the ramp to the next area.
Once you take out the Geth Trooper outside, head to the left to find the SMG Ultralight Materials III. Here you can see the blast shield begins to close in order to protect the base. Legion informs Shepard that he must override the controls, and reopen the blast door before the orbital strike will be effective.
Turn around, and head straight down the outside perimeter to find a way back inside. Geth Troopers will immediately drop in to try and stop you. Utilize Tali’s Sabotage abilities to help temporarily convince some Geth forces to join your side, and take down whatever Geth reinforcements arrive as you continue back towards the interior. Some Geth Rocket Troops will appear on the balcony to your left as you progress. Take them down, and then move towards the computer terminal at the end of the path. There you’ll find a Geth Plasma Shotgun and some Data to salvage.
Head through the door and into the next room. There’s another terminal with Data to salvage and a Med Kit. Follow the hallway until you reach the next door. Once you’re in the next room, more Geth will show up. Head to the left, taking out any Geth you come across. The Door Override will be on the computer terminal on this side of the room, but it won’t be active until you take out all the Geth. As soon as you activate the override, Geth reinforcements show up. After taking them all out, you need to head to the terminal around the corner to the right of where the Geth reinforcements arrived. Activate the second override, and then proceed around the walkway to the elevator.
Right when you arrive at the elevator, a Geth Prime arrives with a few Geth Troopers. It will be a short fight with your whole squad able to focus their attacks on this small group of foes. Once he’s down, take the elevator up to the next level. Three more Geth Primes are waiting for you as soon as you exit the lift. Grab the Geth Spitfire on your immediate right, and lay into the enemies. The Spitfire will make short work of the Prime’s shields and armor. If you run out of ammo, there is more directly to your left.
Proceed straight ahead to the balcony. Once there, use the targeting laser to direct the Normandy to fire on the Geth base. After being hit with a direct shot, the base begins to rumble, and you discover that you just fired upon a hidden Reaper. The monstrous construct arises from the silo, and you’ll have to make a quick run for it to make it to the hovercraft alive.
A short chase sequence happens as you fire on the Reaper from the fleeing hovercraft. It appears the Reaper is down, but after inspecting it, the Reaper flashes back to life. Now Shepard must use the targeting laser to call in three more orbital blasts from the Normandy. Be wary of the Reaper’s incredibly powerful laser while you target it. One hit is all it takes to kill you.
After taking down the Reaper, a cutscene plays out where you have a choice to save the Geth, eliminate the Geth, or force a truce between the Geth and Quarians. The options available to you are based on previous Mass Effect game saves (if you carried one over). Whatever decision you end up making, you’ll return to the Normandy to learn that the Asari councilor wishes to meet with you on the Citadel.