This is the mission that Victus asked you to take on during your conversation with him on the Normandy. He can’t give you the details, but his son and his squad have been shot down on the surface of Tuchanka and need immediate support. Head to the krogan homeworld and land to begin this mission. Reapers will be attacking all around you, rendering the surface of the planet a complete wreck. You will get in radio contact with Lieutenant Victus, who will ask you for backup immediately and inform you that his squad has been scattered across the mountainside. Look to the left to find the SMG Magazine Upgrade, then head to the right and follow the path to begin your search for the stranded turians.
Head towards the ladder on the right and climb up. Follow the path as it turns around and leads you towards a group of three Husks. Your team will mention that you have caught them by surprise, and that you should eliminate them before they can call for reinforcements. Use Singularity and Warp to blow them up or an Assault Rifle and headshots to kill them before they can fetch more. Keep following the path. Examine the ground near where the Husks were to find some Salvage. Climb up the ladder and jump across the gap at the top. Search the ground again to pick up the M-9 Tempest Pistol.
Continue down the path until you reach a group of enemy Cannibals firing upon some turian survivors. They won’t notice you, as they will be busy with the survivors. Keep low and approach the Cannibals without alerting them. Use a charged melee attack to kill one of them. This will get the attention of the others in no time. Mow them down with concentrated gunfire and head to the right, where you will find a ladder. Climb it and look to your left. Here you will find the Sniper Rifle Spare Ammo Mod. Grab it and head to the left.
As you continue onwards, a massive Reaper Harvester will fly in and land in front of you. The Harvester will shoot large projectiles at you, which will hurt a lot if they hit. Take cover and fire upon the enemy with your Assault Rifle. Don’t count on killing it yet, as it will fly away when its health gets low. This will save the turian squad embedded in the mountain’s face. You can also complete this section by simply allowing the turians to die, as their survival isn’t mandatory. Clearly, this isn’t the best option, and if you are trying to play the game “properly” you shouldn’t let them die. It’s not too hard to see to this.
Head down the narrow corridors until you come upon a dead turian lying in the middle of the path. He will be carrying a Phaeston Assault Rifle. Proceed around the corner and search behind the corpse to find the SMG Ultralight Materials Mod. Then head to the left, next to where you found the Phaeston, to find a ladder. Climb down and search to the right to find a med kit before proceeding onwards.
This path will throw you right into the middle of another conflict between the turians and the Reapers. This will be a relatively straightforward battle, as there is little opportunity for flanking or other special tricks. Instead, take cover and focus on eliminating the Cannibals first, then the Marauders. If the Cannibals are allowed to consume their dead, they can become pretty annoying. After you have killed the initial batch of enemies, another Harvester will swoop down and land. This time, you can actually kill the beast, earning an Achievement/Trophy in the process. You will have to do it fast, though. If you can’t pull it off now, don’t worry, as you will have another opportunity to earn the Achievement/Trophy in a few minutes. Otherwise, order your squad to use Biotics such as Warp to weaken the creatures armor as soon as it lands, and cast Warp Ammo or Incendiary Ammo on your guns to make them more potent. Unload with an Assault Rifle or semi-automatic Sniper Rifle while ordering your squad to focus on the massive beast as well to bring it down before it can fly away.
After this battle, head up and to the right. Drop down the ledge here and follow the linear path ahead. After a minute or so of walking, you will find another crashed turian ship. Reapers will again be closing in on their position. Take this opportunity to attack while the enemies are distracted. Keep low to avoid being spotted, and use either a Shotgun or the Biotic Charge ability to deal heavy damage. Infiltrators can use the Tactical Cloak to deal a similar amount of damage. After killing the enemies, examine the left side of the area to collect the Hahne-Kedar Chestplate. Keep following this path and collect the Flight Recorder right after the short drop in the middle of the path. Look across from here to find the Shotgun Smart Choke I Mod. Collect these items and head forward, down the path. Another Harvester will spawn a group of Husks up ahead.
Fire from the hip with an Assault Rifle, or take cover and use a Shotgun to make quick work of the Husks. Examine the ground near where the Husks were spawned after they are dead to find Salvage. Move forward and climb down the ladder. When you hit the ground, look to your left. A Harvester will be here, and groups of Cannibals will already be rushing your position. Quickly find and take cover, then order your squad to do the same. Pop out to attack the rushing Cannibals first. Destroy both of them in quick succession so that one doesn’t eat the other to gain power. Duck down to avoid the projectiles that the Harvester will fire at you. You can either use a similar strategy as you did before to kill the Harvester, focusing armor-weakening attacks on it before firing with powered-up ammo, or you can use your squad to distract it while you pummel it with Assault or Sniper Rifle ammo. If you choose this option, it will free you up to pop out from cover without fear of taking one of the Harvester’s powerful projectiles. Kill the large creature and move onwards.