With the Vaygr defenses penetrated, the Hiigarans can now take the Mothership deeper into the actual asteroid field itself. Although the Vaygr are actively searching for the oracle, they do not have the coordinates of its location. Provided with this by the Bentusi, the Hiigarans will attempt to dock a Marine Frigate with the dig site in order to retrieve it themselves. This mission would be considered somewhat of a stealth mission.
Data from the Vaygr base confirms extensive archaeological digs are underway across this entire sector.
The coordinates provided to us by the Bentusi indicate the Oracle is located here.
We must recover the Oracle before the enemy.
 Primary Objective: Retrieve the Oracle
Auto-save Point – Mission Start
The begins with the fleet exiting hyperspace inside of a massive dust cloud that makes up part of the Gehenna asteroid field. You will have to carry out the majority of this mission within this dust cloud to remain hidden from the Vaygr. Unless you alert the Vaygr, you will not have to worry about defense, as they do not send attacking waves otherwise. You can keep your ships in these fields by right clicking the fields in the tactical overview as though you were giving follow orders. This is the best way to keep your ships in the middle of these dust fields, as doing so manually can be tricky.
There will be two resource spots to begin taking advantage of right away, one directly next to the fleet warp in location and another to the side and just outside the main dust cloud. Send a Mobile Refinery and a few Resource Collectors to harvest from this remote spot, along with one or two squads of strike craft. The reason for this, even without attacking waves, is that at one point the Vaygr may send their resource collectors here, so it will pay to have someone there to ward off any moochers.
You should be able to research level 2 upgrades for the Gunship and Pulsar Corvette. Do this, as it pays off big time given their versatility and the price of the upgrade versus the squads you’d have saved rebuilding. In addition, make sure you research the Improved Torpedoes upgrade to give Torpedo Frigates more power against Frigates and Capital ships. During the mission Ion Frigates will be unlocked, make sure to add a group of these to your forces as soon as they become available, along with researching their armor and engine upgrades.
 Secondary Objective: Destroy the Garrisons
Soon after your arrival, Fleet Intelligence will notify you of three separate Vaygr garrisons in the area. These will need to be taken out first. The garrisons will be refereed to by the direction you would see them in if looking in the same direction your Mothership was facing upon warping in. The right most garrison would be the one considered closest to the Oracle dig site, and in the same dust field “arm” as the Oracle dig site itself.
[2a] Destroying the Right Garrison
Take a force consisting of most of your strike craft along with a small handful of frigates to make the trip towards the right most garrison by navigating through the dust field arm. Keep your elite squads behind the main force if you plan on taking them along, since whoever is at the front of the group will get torn apart by combined fire from the Vaygr forces due to how the dust cloud also obscures regular sensors. Move your forces carefully while on aggressive stance to make sure they pick their own hostile targets as soon as possible.
Once within range you will encounter a group of mainly Assault and Missile Frigates guarded by a large handful of Gun and Missile Platforms and a smaller group of strike craft. Generally speaking, your Corvettes are the least likely to suffer damage, as their anti-corvette weaponry is limited and most of the defenders are best suited to attacking Fighters and Frigates. It is also likely that some of your units might temporarily leave the dust field. If this happens, you will have 40 seconds to coral the stragglers back into the dust field before the Vaygr notice you and start attacking. You really want to avoid this for now.
One last critical point of note, is that you cant just dock damage squads like in other missions. You need to navigate them through the dust cloud arm, back towards your main fleet first or else you will risk alerting the Vaygr, as the ship will likely travel in a straight line to the nearest Carrier or the Mothership. Once your forces have wiped clean the garrison (platforms don’t count and can be left alive) navigate them back to your main forces and dock damaged squads for repair.
[2b] Destroying the Middle Garrison
While you repair damaged squads and most of your first attack group is on its way back, you can start organizing the second strike group against the middle garrison. If you left most of your frigates from before, you can start moving your frigate group up the dust cloud arm to get them on their way to the next fleet, with strike craft catching up as they become available again. Moving through these dust clouds is the most time consuming part of this mission.
Reaching this garrison is particularly best done using the Tactical Overview move-to command on the dust fields, since due to the way the arm raises up along the Z plane, moving manually is a quick way to exposing your forces. Again this group consists of a similar consistency as the first (and third) garrisons, so following a similar strategy works, although allowing your frigates to be at the front of your group and the first seen by the Vaygr can save you some fighter squads. Once you’ve managed to wipe this second group of Vaygr out, its time to navigate back through the dust field arm and prepare the final attack force.
[2c] Destroying the Left Garrison
While the force you sent against the second garrison is still on its way back, its time to get the final push ready. This time, take the Destroyer you should have from the previous mission (Seriously, its worth going back for if you didn’t) and let it lead your forces this time around. You will want the Destroyer to be the unit you move, with a massive force set to guard it, along with at least 2 Resource Collectors that are on repair orders, so they can instantly start healing the Destroyer when it takes damage. Make sure to send a carrier, so you can dock and repair strike craft, and a Marine Frigate, for capturing the oracle, behind the main forces.
One you’ve fully massed up, take the Destroyer led force towards the third and final garrison. You will want the Vaygr Destroyer to be the first unit seen by the enemy so it ends up “tanking” most of the damage for the rest of your forces. Once you engage the garrison, allow your guarding forces to sweep over the enemy which should be focused on your capital ship. This will allow for the quickest removal of these pests. Make sure to keep an eye on the Destroyer’s health, and if it falls to far you can pull it back to keep it alive, you don’t want to lose it yet. Upon vanquishing this final garrison, Fleet Intelligence chimes in and its time to start wrapping things up in Gehenna.
Auto-save Point – Garrisons Destroyed
 Secondary Objective: Destroy the Vaygr Shipyard (and Carrier)
At this point there are two somewhat unorthodox methods to continue this mission and destroying the Carrier and Shipyard situated next to the Oracle. At this point with the garrisons gone, we will actually want the Vaygr to notice our forces, since the only remaining enemies are the ones stationed by the Oracle, doing this will split the defenders into two groups, allowing you to engage the mass of frigates separately for the massive group of Gun and Missile Platforms that guard the Oracle. There are two ways to do this, first being just moving some ships out of the dust field. The second option is to reload the auto-save you just triggered. Loading the save will trigger the Vaygr to send Probes everywhere across the map, which causes your forces to be instantly discovered.
With the Vaygr forces noticing you, prepare your forces to meet the attackers which should head to your group near the ex-third garrison. At this point you can even place some probes around the edges of the dust field to get a little better overview of what is going on. Put your forces in formation and allow the Vaygr to smash themselves against your might, which should happen relatively quickly.
Once you’ve cleared out the last of the enemy frigates, send your frigates in to start working over the platforms (Ion Beam frigates are lovely against platforms) and once the frigates engage, you can follow up with your strike craft. Alternatively, you can wait for further repairs to your Vaygr Destroyer and use it as a tank again. Once you have most of the platforms handled, start focusing on the Carrier and Shipyard. Having your Bombers target and destroy the production facilities (primarily the frigate ones) will make this go a little smother on your forces. At this point, the biggest time consumer should be wearing down the Shipyard.
 Primary Objective: Retrieve the Oracle (cont)
Once the Carrier and Shipyard go nova, the mission is pretty much a wrap. Let your forces take out any possible stragglers while you send your Marine Frigate to dock with the Oracle dig site. With the Shipyard and Carrier destroyed, doing this will pretty much end the mission instantly, with the Pride of Hiigara integrating the Oracle into it’s systems. This event is quickly followed by the Oracle taking command of the Mothership’s hyper-drive engines and forcing the fleet into an immediate jump to an unknowing location. Don’t worry however, the smaller ships will make the trip as well even though they never technically docked.
Gehenna Walkthrough Video