Priority: Tuchanka

Acquisition
The mission is acquired automatically after completing Priority: Sur'Kesh.

Walkthrough
To complete the treaty between the krogan and the turians, Urdnot Wrex (or Urdnot Wreav, if Wrex did not survive) insists that the genophage must be cured. To do this, the cure to the genophage must be dispersed at the top of the Shroud, a tower installed by the salarians to clean the atmosphere of Tuchanka - and covertly used to disperse the initial genophage virus.

The Convoy and Catacombs
The mission starts off with Shepard heading towards the Shroud in a convoy with Wrex, Eve, Mordin, Wreav, and Krogan warriors. The reapers have anticipated an attempt to cure the genophage; to counter this, a Reaper Destroyer has been deployed near the Shroud. To destroy it, the krogan plan to attack from the ground while Turian fighters deploy for air support.

However, the air support arrives too early - a Turian fighters is shot down and hits the bridge in front of Shepard's vehicle, forcing Shepard to find an alternate path forward to the Shroud.

The only path left is to enter the Catacombs, an ancient Krogan burial site which has been in disuse for millennia. Shepard discovers that the area around the shroud is home to "Kalros, the mother of all Thresher maws."

Krogan Ruins
Shepard exits the Catacombs into above-ground ruins, and is surprised to find some plant life - evidence that even with most of Tuchanka ground into rubble and dust, life can still exist there.

As Shepard progresses, resistance is encountered in the form of Reaper ground troops. At the same time, the Convoy is attacked by Kalros - the Mother of all Thresher Maws. One truck is destroyed, and Urdnot Wreav dies if he has not replaced Wrex.

Shepard and the remnants of the Convoy reunite to form a plan for dealing with the Reaper and reaching the Shroud.

The Maw Hammers
Shepard agrees on activating the ancient Maw Hammers to attract Kalros to the area, and hopefully goad it into attacking the Reaper. Shepard heads out activate the Maw Hammers, and Mordin starts finalizing his work on the cure to the Genophage.

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. 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.

At this point, Shepard may either let Mordin go or stop him, to sabotage the cure per the Dalatrass's request. If Shepard lets Mordin go, he is successful in repairing the STG sabotage and the genophage cure is successfully released. If Shepard stops Mordin, the sabotage makes the release of the cure completely ineffective.