Act 3 – Tacitus Regained
In the last scenario the Brotherhood will get it's chance at regaining Tacitus. The precious artifact is kept at a GDI base guarded by energy barriers. Before you'll be able to send in the saboteurs you'll need to get rid of the force fields.
Your base is situated in the south–eastern portion of the map. Start your mission by building a second refinery to speed up the Tiberium–gathering process of the nearby field. Your remaining funds should be spent on crating defensive perimeter consisting of Shredders, Obelisks of Light and SAM turrets. Cyborg units you have received at the beginning of the mission will also come in handy – get your units onto the reckoners and then deploy them near your turrets.
The enemy will send loads of units at your base, so make sure your defenses don't have weak links and start producing Venom helicopters. Several Venoms with super charged particle beams should be placed near the turrets as a support against missile infantry.
With the defenses in place it's time to prepare a counterstrike. Build every building you might need and start developing new technologies. Build more Venoms and send them to scout the area.
Try to reveal as much as you can – focus on revealing enemy structures and Tiberium spikes. During this process you should also reveal two bonus objectives. Ignore them for now and continue building up your army. My choice would be the Venoms as they are fast and perfect for quick strikes and hit and run strategy, but they are not a necessity here.
Before launching your offensive you should secure the Tiberium spikes and a silo west from your positions. They should improve the income rate and the process of building up your forces. GDI will try to recapture these structures, so you'll need to send in some troops to defend them.
1 – Destroy GDI Power Plants
Start your offensive by attacking the power plants marked by Kane. You can't get to them through lands, so your best option are the Venoms or Vertigos. If you're high on resources you may also consider nuking the power plants.
2 – Destroy GDI Bunker Entrances
Unpowered turrets will become an easy target allowing you to move more freely around the map. Start the GDI units and structures of the map but don't miss the Bunker Entrances set between the rock formations. Destroying them will fill your last bonus objective.
After several minutes GDI forces in the area should become a sad memory. The enemy will send various troops at your base, but they shouldn't be much of a problem. Split your army into three parts and send them to defend the GDI communication centers marked with yellow dots on the map.
1 – Capture and Hold GDI Communication Centers
Create three saboteurs and send them to the buildings. The command will initiate the process of disrupting the energy barriers which takes about ten minutes. (If you capture all three centers the process is thrice as fast). GDI will send troops to reclaim the buildings, but if you destroyed the bases defending the barriers they shouldn't be much of a threat. If the situation gets hot remember that you can repair the damaged structures.
After five minutes the first barrier will drop, allowing you to attack previously inaccessible GDI structures. This part of the map will be defended by MARV so focus your attacks on it before it manages to deal some real damage. With the firepower of all of your units it should soon become history.
2 – Capture Tacitus Containment Structure
After the next five minutes second barrier will drop – destroy all remaining buildings and create a saboteur to capture the marked building. This should conclude both the mission and the campaign – Congratulations!