Part 12Update 12:
Intro: YouTube DailyMotion
Mission: YouTube DailyMotion
Finale and Credits: YouTube DailyMotion
It's time to bring down the Brotherhood of Nod and make Kane look like a fool. We get to see several references to Tiberium Dawn, so that's neat. Then we fight Petrova, rescue Sydney, and finish destroying the Temple of Nod. The Mobiuses are reunited and Havoc flies off into the sunset. But then what?
Havoc was promoted to Colonel for his efforts. With the help of MIT, he was able to retcon Tiberium poisoning so it isn't fatal if you're smug enough. This breakthrough allowed him to live well into his nineties. Havoc was a strong proponent of walker-type vehicles such as the Mammoth Mk. II and Mk. IV tanks. Wait a minute... loves mechs... Japanese girlfriend... oh god.
Dr. Ignatio Mobius went back to his research. He died during an ion storm because the bunker he was hiding in wasn't designed to take a direct hit from a lightning bolt. Seriously, fuck ion storms.
Dr. Sydney Mobius went back to not existing.
Kane wasn't even in the Cairo temple. He was probably laughing his ass off at Havoc from his swank bachelor pad in Sarajevo during the entirety of mission twelve.
The praise for General Locke's triumph at Cairo was short-lived. Not long after the battle, longtime rival General Solomon kicked Kane's ass at Sarajevo for real. Then Solomon got all the attention and Solomon got to be supreme commander of GDI and Locke probably died alone, un-loved, and incredibly pissed off.
The Dead Six, having fulfilled their oath to General Locke's great-great-grandfather, were finally freed from the shackles of unlife and went to their eternal rest.
Sakura probably found another merc gig somewhere.
Seth's attempt to achieve greatness by being killed, then brought back as a Death Knight ended badly when the explosion at the Cairo temple vaporized his holding tank.
Being at the epicenter of a nuclear blast gave Light Tank superpowers and sapience. He began a new life as a wandering hero and the people celebrated his one-tank war against the forces of evil. The radiation he emitted wherever he went? Not as celebrated.
That's it for the single-player campaign. What's next on the menu? A long, arduous struggle to get multiplayer working for everyone who wants to participate. Also: bonus videos.