Re: Personally I'd like a pre-quel
Here's my idea:
That Unobtainium is good stuff. You think Earth is just going to leave alone? No, they are sending back a new ship, and this time going prepared. Not only does it have a real military force, but after the events of the first movie they know not to discount that 'spiritual' rubbish - there is proof that the planet has an interconnected neural network spanning species, and human technology is rather good at interfacing to neural networks now. After all, they can sync brains between a human and an avatar body.
Sully has been living the life of a native for the last ten years, and now fits in as one of their own - his off-world origins almost forgotten. He is happy in this life, but for one flaw: Children. His body is still half-human, and infertile, a condition that adversely affects his relationship with whats-her-name from the first movie - family lines are very important to na'vi, and is inability to sire a future priestess is an insult to the community.
One day Sully jacks into a tree, an is passed a vision by that transcended scientist woman, taken from the memories of a Na'vi from the area: The sky is falling. Great birds, trailing fire, dropped from the clouds. To the distant tribe this is a worrying and incomprehensable event - but Sully recognises the description of a spacecraft in reentry and landing. He knows that the tribe there knows almost nothing of humans - he is the sole Na'vi expert on them. So he and whats-her-name travel to this costal region to learn what is going on, and to defend Pandora if they must.
On arrival they find that the humans have been more sensible this time. Aided by mapping data from the previous operation they have set up in a less tropical region, where the local wildlife is a little less dangerous. Further, they are mining offshore - a costal base serves as a dock, while giant dredgers scoop unobtainium from a seabed deposit. This is promissing: They won't need to expel anyone from their land. What's-her-name expresses hope that maybe coexistence is possible - but Sully is suspicious, and concerned that the deposit will eventually be depleted. Further, there are already signs of water pollution from the toxic refining process. Sully tells whats-her-name the basic base layout.
Further strange activity is noticed too. The animal life is acting strangely. The locals report that the trees are giving them strange visions. Sully investigates this by jacking in himself, and sees strangely familiar things: Human writing, pictures and symbols. Things that have no place on Pandora. Still spying on the Humans, Sully, What's-her-name and one of the locals are caught and taken into the human base. Sully plays dumb, pretending to be a technologically ignorant native so he can try to observe inside - he sees scientific equipment through the windows, computer banks, screens displaying MRI data and networks and a bank of avatar interface tanks on his way to a holding cell before someone notices his extra fingers. This confuses the humans - they see an avatar body, recognise Sully, but say they have none themselves and ask where his tank is. Sully confesses that he no longer needs his human body, but this sounds impossible - he is dismissed as crazy.
Sully escapes - not using his knowledge, for Avatar isn't that type of franchise, but because the three of them are able to cooperate to break out. As they flee, Sully witnesses something even stranger: A dredger dumps its load into a floating barge, before a whale-analog swims up to the surface and starts pushing it towards the human base. This triggers a crisis of faith for the Na'vi: If the animals are aiding humans, that means Enwya is on their side. How could the Na'vi be abandoned by their goddess?
Whats-her-name cannot accept this, and nor can Sully: He has seen what humans do to a world. In a search for answers he attempts to make contact again with dead scientist - but this time when he jacks in, he is bombarded with noise and scattered imagery. Pictures of earth, chemstry, space travel, and through it all the sense of others - sensing him, reacting, chasing him down. Dead Scientist struggles through this chaos, but can only guide him to a key image stronger than the rest: A map.
Sully, whats-her-name and a few escorts are guided to the ocean and swim down where the map says. There they find roots - a tree of souls, made of coral and concealed below the water. The locals say they knew of this place, but it is a most holy site and approached only on the rarest occasions. The humans have found it already: Technology covers the natural formation, with cables running undersea towards the human base. Now he understands.
Humans learned to control an avatar body. Now they no longer need one. They can be the animals. They can be the planet itsself. This time Enwya isn't going to come to their aid - she is too overwhelmed by the humans now hooked up.
Before the team can consider disconnecting the device, an ambush of very hostile wildlife arrives to claw and catch them. The local human defenders. The team escapes, barely - but as they look back they see the place heavily guarded by pandoran crabs.
Now things escalate. The local tribe are first disbelieving, then outraged at this sacrilidge. A war is declared - but Sully knows they cannot win this time. They defeated a mining operation before, but barely, and only with aid they won't have a second time. Now they are up against a full military force. Worse - flying drones are broadcasting a message: Hand over the human and avatar, or face destruction. No more nice hippy humans now: They are in a state of war.
Whats-her-name asks to trust in Enywa. Sully realises this could work - and Dead Scientist tells them how. Enywa is overwhelmed with alien thoughts - mining plans, ore transport routes, the idle background of the operators as they think of home. But that could go both ways. As war is launched (The locals riding into battle on giant mantas), a daring operation is carried out to capture one of the crabs and link Sully to it before the operator can disconnect. Contact established, Sully is able to use their own tech against them - disrupting the control system long enough for a whale to bite through the undersea cables. Even then the battle goes badly, with human weaponry slicing the incoming Na'vi before they can get close - but whats-her-name sees an opening. Flying overhead on her lizardbirdthing she dive-bombs, making an abrupt landing inside the base in the area Sully earlier told her was the environmental room. She doesn't know tech, but she can break things - pulling pipes, smashing controls, stabbing her spear through panels and tearing tanks apart. With the base now flooded with Pandoran air, the humans have no option but to set the auto-destruct and run to their shuttles.
Say is saved, humans defeated, Sully and whats-her-name once again hailed as heroes. Oh, yeah - they find an orphaned na'vi to raise too. Everyone is happy.
Cameron: If you use that, I'll settle for even a tiny 0.1% royalty - that's still a lot of money to me. And I want that gross, not net - I'm not stupid.