With the Avatar 3 trailer playing before screenings of The Fantastic Four: The First Steps, I was lucky enough to see it early. My reaction? Boy, you’re in for a treat.

Still, it's understandable if you're in need of a refresher about that past, present and future of Cameron's corner of the galaxy. Here's everything you need to know about Fire and Ash before you catch the trailer in theaters.

Right from the outset, it's clear that "Fire and Ash" will be the most intense chapter in the "Avatar" saga yet. For the first time, we see hostility amongst the Na'vi clans, with Jake Sully (Sam Worthington) and the oceanic Metkayina clan drawn into a conflict with the Mangkwan clan, or Ash People, as they're also known.