The original Blade Runner wasn't exactly defined by its plot, being more of an experience. The basic story was that Harrison Ford's blade runner Rick Deckard comes out of retirement to hunt down four rogue replicants - artificial humans with four-year lifespans made for off-world labour, with director Ridley Scott's hard-baked sci-fi noir really being more about exploring the nature of life and creation.
With the current glut of legacy-quels and glorified remakes it would be reasonable to expect the sequel, Blade Runner 2049, directed by Arrival's Denis Villeneuve, to do something similar, just with Ryan Gosling the lead. However, while comparatively little is still known about the film, it certainly sounds like we'll actually be going into new territory with the sequel.
TrailerTrack, which monitors the classification and release of new teasers for upcoming films, has posted an official synopsis for Blade Runner 2049 that gives us an idea of what the general story is:
Thirty years after the events of the first film, a new blade runner, LAPD Officer K (Ryan Gosling), unearths a long-buried secret that has the potential to plunge what's left of society into chaos. K's discovery leads him on a quest to find Rick Deckard (Harrison Ford), a former LAPD blade runner who has been missing for 30 years.
So the basic set-up is that K must go on a secret mission to track down Deckard and uncover the secret of this world. This chimes with several rumors surrounding the film that point towards Ford's returning character playing a more background role in proceedings and confirms that Gosling is indeed playing one of the titular robot-hunting cops. As for what that long-buried secret is, that's surely going to link back to the original film. Could it be the knowledge that a new type of replicant was developed with a lifespan longer than the legal standard of four years? If so, that would mean future humanity may be more robot than man (and have major ramifications for Deckard, who fans agree is most likely a replicant).
This also suggests this 2049 version of LA is even more run down that the overcrowded, rain-blighted take from the 1982 film (set in 2019) - things are on the brink, with humanity fractured akin to the set-up of Phillip K. Dick's source novella, Do Androids Dream of Electric Sheep? (possible by off-world travel). We've got a couple of pieces of concept art to back this up, as well as Gosling's character's typically sci-fi name, K (it's a reference to author Dick, yes, but the single-letter could also be setting up the character as a replicant).
The synopsis posting also came with the suggestion that the much anticipated teaser trailer could be dropping today. This would presumably be the last of what has been a massive trailer deluge in the tail end of 2016 - and what a movie to end on. Stay tuned for (hopefully) much, much more on Blade Runner 2049.