Priority: Tuchanka

The plan to disperse the genophage cure has been complicated by the arrival of Reaper forces, who have occupied the area near the shroud tower. Get Eve safely to the tower.

Acquisition
This mission is automatically available after completing the prior plot mission.

This mission is a "point of no return" and will trigger Priority: The Citadel II automatically after completion. Be aware that some NPCs on the Citadel will disappear preventing some side missions to be turned in for completion afterwards.

Preparation
Immediately after completing this mission, Priority: The Citadel II becomes available, which makes it impossible to visit the Citadel and causes a number of side missions to be lost forever. As such, completionist players should be sure to complete the following side missions before attempting this mission:
 * Benning: Evidence
 * Citadel: Alien Medi-Gel Formula
 * Citadel: Barla Von
 * Citadel: Biotic Amp Interfaces
 * Citadel: Hanar Diplomat
 * Citadel: Improved Power Grid
 * Ismar Frontier: Prototype Components
 * Any interactions with Kelly Chambers (only available if she survived the Collector Base assault in Mass Effect 2). If you visit her before starting this mission and telling her to "change identity", she'll survive the Cerberus assault on the Citadel and stay available.
 * Conversing with Matriarch Aethyta in the Apollo's Cafe, as she will disappear after Priority: The Citadel II.


 * Tuchanka: Turian Platoon, Tuchanka: Bomb and N7: Cerberus Attack stay available after completing this mission.

Walkthrough
As mentioned above, it is advisable to complete any and all business on the Citadel before commencing this mission.

To complete the treaty between the krogan and the turians, the Urdnot Clan leader insists that the genophage must be cured. To do this, the genophage cure must be dispersed at the top of the Shroud, a tower installed by the salarians to stabilized the atmosphere of Tuchanka and covertly used to disperse the initial genophage virus.

Travel to the Krogan DMZ and the planet Tuchanka, and land at the Shroud site. You will discover that the Reapers are using a Reaper Destroyer on the Shroud in order to poison Tuchanka's atmosphere. To destroy it, the krogan plan to attack from the ground while turian fighters deploy for air support. You will also be informed by the Salarian Dalatrass that the Shroud has been sabotaged to prevent dispersing a cure, and that you could choose to trick the Krogan in to thinking that you dispersed the cure but keep it from working in return for getting support from the Salarians.

Defend Eve
You will then take a shuttle down to the surface. The Urdnot leader sent word for the krogan clans to assemble at the Hollows, a sacred krogan meeting ground. During the conversation, you can reveal about the Dalatrass' offer to sabotage the cure or just remain silent. If you choose to reveal, you will be interrupted instead and a message that the Hollows are under Reaper attack. When you reach the Hollows, you need to fight off waves of Husks swarming the area. You will gain 300 experience points after successfully holding off the Husks. In the ensuing scenes, if Wrex is alive, tensions amounts between him and his brother, Wreav. If otherwise, bickering between Wreav and Jorgal Thurak takes place instead. Eve intervenes during the rising conflict and make a rallying call for the krogan to unite against the Reapers.

The convoy
The krogans head out in a convoy towards the Shroud. While travelling, you given the option again to reveal Dalatrass' deal or keep quiet about it. Soon after, the convoy came to an immediate halt and the team gets down. You can pick up a Shotgun Smart Choke upgrade, a Pistol Magazine Upgrade, a Pistol Melee Stunner, a Death Mask helmet armor, Graal Spike Thrower shotgun and 2 Med-kits. Speak to the Krogan Scout who tells you that the road is damaged and the convoy can't proceed further.

However, the turian air support has already begin their attack. A fighter is shot down and hits a truck. Shepard radios the Urdnot leader to get out while you have to find an alternate path to the Shroud. At this point, you gain another 150 experience.

The only path left is through the ruins. Jump over a gap and head into the tunnel.

Escape the catacombs
You're now in an ancient krogan city which has been in disuse for millenniums. Go down the stairs into the first room, and either jump through the gap off the ledge on your left, or go down the next set of stairs to your right. In the second room, there is a door to your right and to your left. Go through the door on the left, and on the right hand wall of that room is an Ancient Krogan Artifact, which is a painting on a wall, worth 8,500 credits. Return to the door on the right, go down the stairs. Right before another jump down, Shepard and team experience strong tremors. Eve suggests that Kalros, the mother of all thresher maws, lives in the region.

Jump down the ledge at the end of the path and turn to the left. In the far end of this area, you can salvage another Ancient Krogan Artifact on the wall for 8,250 credits. After retrieving it, go to the other side of the room and turn left into a tunnel where you'll find the final Ancient Krogan Artifact, a painting, worth 8,250 credits on the right. Further along the path, you can examine a dead Ravager and then head up the stairs into the light. You will gain another 300 experience after exiting the catacombs.

As you move forward, you will fight a wave of Cannibals and Ravagers. Then when you move forward again, a second set will drop from the sky. Once they are finished off, move forward and turn right to jump over the gap. A set of Cannibals will appear followed by some more coming around the corner, and finally one of the Brutes will come around the corner. The second wave is only encountered after leaping over a gap, and the enemies, including the Brute, cannot follow you if you leap back over the gap after triggering them allowing you to kill them without risking direct combat.

After the second wave, move forward and then go around the U-turn and up the ledges on the left. At the same time the Krogan's will be talking about a plan to stop the Reaper but Eve will say that the commander has enough to worry about. Once you are up the stairs, a third wave of Cannibals, Husks, and Ravagers will attack. Once they are dead, head for the right side of the open area toward the Krogan statues.

Upon reaching the second bridge, Kalros appears and chases the convoy while damaging the bridge in the same time. Jump over the gap and go to a memorial area further up. As you approach the small bridge, a wave of Cannibals and Husks will attack. After some more dialogue with the convoy, more Husks will attack along with some Marauders. Once they are dead, you will find a SMG Scope upgrade on the left side of this area. Head down and back up the two short set of stairs where the Marauders came from and find an Assault Rifle Extended Barrel upgrade on the left.

Turn right and drop down of the edge of the series of ledges toward the dunes to trigger a cutscene where Shepard and team board the convoy but the second truck carrying Wreav is pulled into the ground by Kalros.

The maw hammers
Eve suggests using the ancient Maw Hammers to summon Kalros to the area and distract the Reaper away from the Shroud. Shepard agrees and head out to activate the maw hammers, while Mordin or Padok Wiks heads out in another direction to finalize a cure to the Genophage.

Clear off the two sets of Cannibals and go up a flight of stairs on the left. At the top of the stairs, pick up a M-5 Phalanx Heavy pistol. When you attempt to cross the bridge nearby, the Reaper blasts the bridge and Shepard falls down below. From here, the Reaper starts blasting at you until the turian fighters appears to distract it. The first hammer you activate gives you 300 experience points.

To reach the controls to the two maw hammers, Shepard has to fight through a gauntlet of Brutes, while avoiding getting crushed by the Reaper. Kiting the Brutes is an option, particularly if armor-damaging skills are available. Alternatively, simply dash through the battlefield, activating the maw hammers via superior speed.

At this point, the Reaper's legs are the biggest threat: one hit will knock off your shields and at least one lifebar segment; if the Reaper lands a second hit before your shields regenerate, it's an instant kill. Thankfully, the Reaper's leg seem to be land when you approach specific locations of the area. Many of the stabs are focused on the two catwalks leading to the maw hammers. As such, the safest approach is to run across the arena and then walk down the catwalks. Also, you can see where the Reaper is going to hit roughly two seconds before it happens by looking for the giant shadow cast by its leg. That's enough time to dash to the side and avoid running into the thing.

When both hammers have been activated, they successfully attract Kalros, which destroys the Reaper.

The Shroud
With all opposition from the Reapers destroyed, Shepard and the convoy approach the Shroud. However, the Shroud sustained damage in the fight against the Reaper - it is falling to pieces as Shepard and Mordin approach. Mordin must travel to the top of the tower to counter the STG sabotage which was installed years ago by the salarians. Mordin is also tasked with overseeing Eve's well-being; if he lacks Maelon's data, she will die whilst Shepard is tangling with the Reaper.

At this point, Shepard may either let Mordin go or stop him, to sabotage the cure per the Dalatrass's request. There are multiple outcomes to this conversation:


 * If Shepard did not reveal the sabotage while in the convoy to the Shroud, Mordin will realize something is wrong. Either Shepard tells Mordin about the Dalatrass's deal or Mordin will correctly surmise it. Mordin will ascend the tower to repair the STG sabotage, successfully releasing the genophage cure, but dying in the process.


 * If Shepard warned of the Dalatrass's deal in the convoy, Mordin carries through the counter-sabotage and deploys the cure, sacrificing his life in the process. You may use a Paragon interrupt just before Mordin steps into the elevator to get some morality points, but it won't change Mordin's fate.


 * Alternatively, you can attempt to stop Mordin using normal conversation. If so, Mordin insists on continuing, and Shepard is forced to use a Renegade interrupt to gun him down.

It is currently unknown at this time if having Padok Wiks present instead of Mordin also opens or limits outcomes. Since the interaction between Wrex/Wreav, Mordin/Padok and kept data/deleted data result in at least eight separate outcomes, multiplying to a possible 16 outcomes once the above choices are factored in.
 * If Wreav leads Clan Urdnot and Eve died, Persuade options can be used on Mordin to convince him that it is for the best if the Shroud remain sabotaged and the krogans fooled into believing the genophage cured. Mordin fakes his own death and becomes a War Asset at the Crucible project.

Enemies

 * Brute
 * Cannibal
 * Destroyer
 * Husk
 * Ravager
 * Swarmer

Aftermath
This mission results in the following outcomes:
 * The turians enlist as War Assets.
 * Whether or not you actually cured the genophage, the krogan enlist as War Assets. However, they may be diminished in strength if Eve died. Furthermore, if you did not cure the genophage, Wrex will eventually find out, and emerge from the elevator to confront you during Priority: The Citadel III, leading to Wrex's death and a further diminishing of the krogan's military strength.
 * If Wreav is the Urdnot leader, he never discovers the deception. However, he isn't able to do a very good job of holding the krogan together, leading to diminished krogan value as War Assets and as defenders of Palaven, at least according to Primarch Victus during Priority: Earth.
 * If you cured the genophage, you will receive no salarian assets at this time, leaving the STG force you gained from Major Kirrahe (if you did so) as their race's only representatives. However, the events of Priority: The Citadel II--the very next mission--will give you a chance to win their respect. If you were able to spare Mordin, he will enlist as well (according to the steps above, it is not possible to both cure the genophage and spare Mordin).

Given that the Salarian First Fleet's military strength is 150 points while the total combined military strength of Clan Urdnot and Wrex is 325 points, a Renegade-minded player should be aware that not curing the genophage will actually weaken your force. However, this has not yet been confirmed for all cases of failing to cure the genophage, but merely all cases of killing Mordin plus all conversation options during Priority: The Citadel III.