As far as any actual release window, while it is very early in the process BioWare is targeting a late 2014 to mid-2015 release for the fourth installment in the franchise. Sources say that this news means we most likely will not be seeing Mass Effect 4 on the Xbox 360 or PlayStation 3, but instead on the latest consoles from both Microsoft and Sony that are now expected to arrive in the fall of 2013.
As for what the next Mass Effect will be about, no one other than BioWare seems to know. The company has taken a reading of fan opinion and whether the game should be a prequel or another continuation of the current Mass Effect story line. So far, however, no really knows what BioWare is planning.
Right now, about the only thing we are sure of is that lead character “Shepard” is returning to be a part of Mass Effect 4. This is about the only thing that is confirmed.