After completing one of the two previous missions, you can now head to Tuchanka to cure the genophage. You’ll discover the only way to effectively save the Krogans is to upload the cure into the Shroud, which is now surrounded by Reapers. Once you decide to land, the Salarian Dalatrass will contact Shepard. She informs you about a secret failsafe left in the Shroud that will trick the Krogans into thinking the genophage has been cured, but will not allow them to procreate.
On the flight down to the planet, Eve notices Shepard is distracted. You have the option of revealing the Salarian plan to her, or keeping to yourself. This conversation will come up again a second time while driving to the Shroud in the Krogan transport. If you choose to keep the secret to yourself, you can choose how to deal with the Krogans at the end of the chapter. Revealing the Salarain plans to Eve at either point means you are effectively choosing to cure the genophage. Siding with the Salarians will give you their aide in completing the Crucible, as well as their ships, but you lose out on help from the Krogans. The same is true if you decide to cure the Krogans.
When you land on Tuchanka, Husks are all over the landing zone. You’ve got to take them all out before Eve can leave the ship. After you do so, a cutscene takes place where another Krogan clan questions Shepard’s plans. Eve settles the dispute quickly, and then you board the Krogan transports to head to the Shroud.
Shortly after departing, the transport comes to a halt. Shepard heads outside to investigate what’s wrong. To your right, there will be a Krogan working on a transport. Next to him are a Shotgun Smart Choke II, a Death Mask, and a Pistol Melee Stunner II. Directly behind you will be a Krogan leaning on the roadway railing. There are two Med Kits and a Graal Spike Thrower. Pick all of these items up, and then turn to the right to find the Krogan Scout. Before talking to him, grab the Pistol Magazine Upgrade to his right.
After a short cutscene, Shepard and his squad are stranded. There’s an entrance to some ruins on the other side of the transport wreckage. Hop over the gap, and enter into the ancient Krogan ruins. Head down the steps, and go through the first doorway on your left. Drop down to the next level, and head through the first entry you see. You’ll find a painting on a wall that lets you salvage an Ancient Krogan Artifact. Head back out the door, turn left, and then turn left again to head through the next entry and down the steps. Shepard encounters a series of tremors, but Eve reveals the tremors might actually be a giant thresher maw.
When you drop down, proceed around the rubble, and head straight. There’s another Krogan painting. Salvage the Ancient Krogan Artifact, then turn to follow the path behind you. Enter through the open door on your left. On the wall to your right will be another Krogan painting. Examine it to salvage the Ancient Krogan Artifact. Continue on this path until you climb up a set of stairs and find yourself outside.
As you make your way through the next area of ruins, a pack of Cannibals and Ravagers attacks. Take them all out, and then continue on exploring the area making sure to pick up any ammo you find. Continue down the path to the right. Jump over the gap in the walkway, and you’ll find another group of Cannibals. Take them all out, and a small pack of Husks will appear along with a Brute.
Dispatch all of the Reaper forces, and then proceed around the corner. Head up the steps on the left. You’ll encounter another group of Cannibals, Husks, and Ravagers. Take time to make use of cover, and eliminate every Reaper before moving on. Move through the doorway and cross the bridge. Follow the path as it winds until you find yourself in an area filled with Krogan monuments.
Head down into the central patio, and you’ll encounter a group of Husks, Cannibals, and Marauders. Take them all out. Continue along the path until you find an opening to drop down on the right. A cutscene plays where Shepard and the Krogans decide the best way to get into the Shroud is by leading the giant thresher maw to the Reaper. To do this, Shepard must activate some ancient hammers that will draw the maw to where the Reaper is holding out.
As you head to the next area, you’ll encounter a small group of Cannibals. Take them out, and then proceed forward. At the top of the steps, you’ll find an M-5 Phalanx. Once you’re in the next area, you’ll find one hammer is located to the right, and one to the left. Dropping down into the clearing causes four Brutes to appear. Taking them on is possible, but ill advised. It’s much easier to just pick a hammer, and run towards it bypassing combat all together. The Reaper will try to stomp on you when you get close to one of the hammer switches. Look for the giant shadow to appear in front of you, and then roll backwards to avoid being squashed.
After activating the first hammer, simply turn around and run straight in the other direction to the other hammer. Again, avoid the Brutes and the Reaper stomp. Activating the second hammer cues up the final cutscene for the chapter. After making it into the Shroud, you can choose to either betray the Krogan or ignore the Salarain Delatrass’ plan for sabotage.
After completing the mission and returning to the Normandy, you learn Shepard is requested back at the Citadel. Now is a good time to speak with everyone on the ship again, and complete any side missions you have. Once you return to the Citadel, some of the missions will no longer be available.