Investigate Research Camp

When you reach the camp, a few Husks will reanimate. Like any other zombie, they'll shuffle towards you, attempting to overload your shields with an electrical burst. Backtrack away from them to prevent them from reaching you, and use Kaiden's Throw ability to keep one of them on the ground while you shoot the others.

When you get past the Husks, move into the camp and attempt to unlock the door with the Decryption mechanic. Save your game before doing so. Decryption is a basic button-tapping game. It will either be easy or difficult, depending on your hand-eye coordination, but if you miss your chance at the decryption it'll cost you 25 omni-gel to override, which you probably won't have unless you break down a number of items. If you can bust through the door, though, you'll find Dr. Warren and her crazy assistant. If you investigate, she'll tell you more about the attack; you can also punch out Manuel.

Head To Spaceport

Make your way to the spaceport over the hill; you can kill the Geth Troopers by firing on the explosives near them. When the Husks are dead, hack the door on the pod nearby to find some farmers. When you attempt to leave them, you can use your Charm/Intimidate abilities, if you have them, to try and wheedle out more goods and information from them. At the very least, though, you'll get a nice pistol. Be sure to check inside the hut, too; there's a locker you can hack into for more goodies.

Just when we were starting to like him.

Head to the spaceport nearby to find Nihlus' body. Before checking it, open the medical crate nearby and look behind the fire for an upgrade kit. When you check out Nihlus' body, a man nearby will tell you what he saw. If you managed to get Cole to give up his contact's name, you can press him for some grenades.

Take The Train

Start making your way down to the train level. There are loads of Geth on it, however, including a Destroyer. If you look carefully, though, there are also some plasma cells that you can shoot to blow them up; that'll help you wean the enemy Geth a bit. The Destroyer will make its way up the center of the train, so take cover and shoot at it as it approaches. If it gets near to you, use Throw and any other abilities you have to knock it out, then sprint down the train to get close to the remaining Geth and destroy them as well. This can be a tough fight, to be sure, so don't hesitate to replay it and get used to the controls here. Your abilities can make all the difference in this fight, so don't hesitate to use them.

Shut Down The Charges

When you get to the other platform of the spacedock, you'll find that the Geth have triggered four charges designed to blow the whole place sky-high. Apparently they're not concerned with their own well-being, either, as they've decided to stay behind and guard the charges in an attempt to prevent you from shutting them down.

Oddly enough, your poor equipment can make this one of the most difficult fights in the entire game.

The Geth here are a lot more difficult than what you've been facing before; there are shock troopers and even a sniper or two in position. They'll deal heavy damage to you, so take things slowly. Stay behind cover as you approach, use your grenades from a distance, and use your abilities to weaken them up or knock them down. Don't worry about the charges until your foes are dead. When you've cleared everything out, return to their positions on your minimap and shut them all down.

With the charges done, head to the other side of the spaceport, where a few Geth await you. Shoot them and the Husks, but be sure to examine the port carefully for containers and lockers before approaching the beacon. When you do investigate it, your mission ends.

Return To The Normandy

After speaking with Anderson, head out to the mess hall and talk to Ashley and Kaiden. This is optional, but you can get into their good graces, or bad graces, depending on how the conversations progress. You can check the CIC area and the navigation area for some codex entries. When you're ready to move on, head to Joker and begin your run to the Citadel.