The gist of the story is that it follows Spock, played by Leonard Nimoy, back in time from the franchise's "current" setting, as Romulans attempt to go back in time to kill the young Captain James T. Kirk before he goes on to do all those things that messed up the Romulans' many plans. So, J.J. Abrams has indeed come up with a clever way to bridge the "old" franchise to his new revamp, and since there is time travelling involved, there's even the possibility that things can be changed, meaning everything we thought we knew could be completely different going forward.

http://www.rottentomatoes.com/m/star_trek_11/news/1752348/weekly_ketchup_jj_abrams_star_trek_plot_revealed