Tuchanka: Urdnot Wrex

This mission, which Commander Shepard can receive quite early in the game, if deciding to first go recruiting a potential krogan team member, as hinted by the Illusive Man (Dossier: The Warlord), ignoring Miranda's advice to first go after the scientist. After finishing the recruitment mission, Shepard ends up with a possible team member in a tank. Should he decide to awake him, Grunt will soon show important signs of stress, which will lead the team on Tuchanka, the krogan home planet, in order to research a solution for Grunt's condition. Upon landing, Shepard is requested to pay a visit to former shipmate Urdnot Wrex, who has acquired a position of power on the planet and might help with Grunt's troubles.