Shepard is requested to meet with the Defense Committee about the Reaper threat. As the committee debates what to do about the incoming attack, the European front comes under siege. It is too late to prepare, as the Reapers have started their invasion. The communications with Europe are cut short, and the Reapers appear just outside the chamber window.
Objective 1: Rendezvous with the Normandy to escape.
Admiral Anderson and Shepard appear to be the only survivors of the blast that took out the chamber. Follow Admiral Anderson out the window, and across the outside of the structure.
As you make your way across the rooftops, you will encounter a small group of Husks. Take them out, and then proceed down the ladder with Anderson.
Once you drop down, a second small group of Husks will appear. You will have to take them out with melee attacks. After defeating them, a Reaper ship blasts the building Shepard is standing on, opening a way inside.
After entering, make your way to the door on the left. A Husk will pop out. Eliminate him, and then proceed through the door, and into the building.
A short cut scene will play, and Shepard and Anderson will find themselves in another part of the building. Pick up the ammo, and then follow Anderson out the window.
As you make your way across the destroyed building, a Reaper ship will destroy a Drednaught. The resulting explosion causes a shockwave that sends Shepard and Anderson careening down to the rubble below. There you will encounter two soldiers hiding from a group of Cannibals. Take them out.
Objective 2: Find the radio on the wrecked ship.
After taking down the Cannibals, head to the crash site with Anderson. As you make your way around the ship, you’ll find a med kit on the right. Just after you pick that up, you will encounter two more groups of Cannibals. Stay behind cover to take them out quickly and effectively.
Once you’ve done that, make your way across the wreckage. You’ll find an M-8 Avenger on the hull just in front of the radio. Pick up the gun, and then activate the radio.
Objective 3: Hold out and wait for extraction.
After Anderson contacts the Normandy, another pack of Cannibals will land nearby. You’ve got to defend your position while you wait for the Normandy to arrive. Cannibals will keep spawning for a few minutes. Try not to leave the immediate area until help arrives.
Once the Normandy arrives, it blasts the remaining enemies, allowing Shepard and Anderson to escape and board the ship. Anderson stays behind, while Shepard and the crew head off for the Citadel to speak with the Council.