I'm rather into spoilers, so be warned, I tend to share whatever I come across that I think is plausible.
As I write this, Star Wars Episode VII is filming. They have kept things under wraps, but in this information age, it is hard to stop information from getting out and getting everywhere.
There have been some pretty wild rumors, ones I tend to discount. I'll stick with the ones that are newer and seem to ring more true for the Star Wars universe.
It is no secret that the core of the original cast is returning (at least for this episode - someone important usually dies in the first installment of a trilogy a la Ben Kenobi and Qui-gon Jinn) along with many new faces.
Han Solo is rumored to be a retired Republic fleet officer and Leia is an important political leader. Luke is rumored to be missing for something like 10 years (the initial reports said since Jedi, but newer sources have reduced that to a more believable span). Mark Hamill is sporting what he calls a required gray beard, making him look very much like his mentor, Ben Kenobi. It appears that the movie starts with a quest for Luke after some of the new characters find his lightsaber. It is unknown if this is the one he lost in Empire (Anakin's) or if it is the one he built in Jedi and the loss is part of the story.
There is more information in the rumors as to the identity of the good guys. Daisy Ridley is Han and Leia's daughter. John Boyega is playing a former Stormtrooper. Someone is playing Lando's Son or Daughter (Lupita Nyong'o possibly?) and Han and Leia might have a son who is flying the Millenium Falcon. The Falcon is definitely in the movie and it looks like in a big way. The interior sets have been built (with the same impossible configuration as ANH and Empire) and a chunk of the exterior. Plus we've seen an updated X-wing.
The situation in the galaxy appears to be that the Empire is smaller, but still in existence and in a state of cold war exists with the Republic.
But they are the real enemy. There appears to be some Sith or Sith-like group who are out to cause trouble, possibly with an immense weapon.
As to the plot itself, it is largely a mystery. We have Daisy Ridley and John Boyega finding the lightsaber. Some sort of rescue of Luke that leads to some conflict where Luke saves the day. But he has changed and he didn't save it in a good way (whatever that means).
My guess is that what has leaked is no more than you usually find in a movie trailer and that the real secrets of the story will remain so until it opens in a little over a year. Though I would hope we get a little more than this. I'll post updates when there is something new to report. Until then, I have a book to finish and Series 8 of Doctor Who to watch.