As was hinted last season, the fifth and final season of FRINGE, set in 2036, will see the Fringe crew battling the Observers, who are no longer simply observing. The season starts one day after the events in the season four episode Letters of Transit. This will be the final season. The producers wrote season four with the mindset it might be the last and felt that the current story was done, thus the move to the future.
FRINGE  returns, on Fox, on September 28th.