James Cameron will be taking moviegoers back to Pandora… but now for another two and a half years (or so), when Avatar 2 finally opens in theaters. The sequel to Avatar – which remains the highest-grossing film of all time unadjusted for inflation – is being shot at the same time as Avatar 3 and Avatar 4, with the latter due to be released in 2018 and 2019, respectively.

It turns out that Cameron already has four movies’ worth of additional story to tell in the Avatar universe, as revealed by his longtime collaborator James Horner. That being said, the seasoned film composer – who won his two Oscars for his contributions to Cameron’s other commercial smash hit Titanic – clarified that the current plan is still to make a new trilogy (not a new tetralogy) of Avatar features, plus the 2009 original.

The original projected release date for Avatar 2 was late 2016, but a few months back Cameron announced the project won’t be ready until 2017, instead – having said that more time was need to develop the film, which is now part of a narrative saga (not a stand-alone sequel). Horner, who attended the Titanic Live event at Royal Albert Hall last night (where the Royal Philharmonic Concert Orchestra performed Horner’s Titanic score), offered some more insight on the matter to Hey U Guys:

“[James Cameron’s] got four [‘Avatar’] sequels script-wise, and he’s trying to make it into three. And I think that’s where the effort is going right now […] how do you keep it from expanding into a fifth movie?”

In some ways it’s encouraging to hear that Cameron has already developed enough potential story to sustain more than three Avatar sequels, as it (hopefully) means the films’ over-arching narrative won’t end up being stretched further than it should be. The original Avatar was by and large admired for its technological break-throughs, but the film has long been criticized for its simple story and less innovative tropes/themes. Which is to say: Avatar 2 (and beyond) having a more complicated and dense storyline to go with the high frame rate 3D and mo-cap effects doesn’t sound so bad.

Standalone Avatar novels – intended to expand upon the upcoming movies – are currently in the works, so it’s possible that some of the ideas that Cameron originally intended to explore in his feature sequels shall be covered on the printed page instead. In the meantime, Cameron is collaborating with four different screenwriters for the Avatar sequels, which means there are five people total deciding what narrative material should make the final cut – and what material isn’t necessary (or interesting) enough to include in the three films being crafted.

At this point, the question is whether or not everyone else will be as passionate to see a new Avatar trilogy as Cameron is about telling these additional stories set in the Avatar universe – once they get to finally watch Avatar 2, that is. The characters and mythos from the original Avatar haven’t exactly prompted the same kind of demand for further examination like other sci-fi properties have before them (think Star Wars, Star Trek, etc.), which is also something to take into consideration (which isn’t at all to say Avatar 2 might struggle, box office-wise).

Then again, we know little to nothing about the new places, people, and non-humans that will debut in the upcoming Avatar sequels; not to mention, the way these movies are being made could allow them to push the filmmaking technology envelope as much as their predecessor did. Those are key factors to keep in mind, as we wait to glimpse just what, exactly, Cameron and his collaborators have been cooking up behind closed doors.

Avatar 2 is now projected to arrive in 2017, followed by Avatar 3 in 2018 and Avatar 4 in 2019.