The next game in BioWare's sci-fi RPG series is called Mass Effect: Andromeda, and it's coming in holiday 2016. Electronic Arts kicked off its E3 2015 press conference with a two-minute CGI trailer for the game.
The trailer starts off with Johnny Cash singing "Ghost Riders in the Sky" and a rear-view shot of a helmeted N7-rank soldier in a warping ship. Later the soldier explored an alien world with some new allies, discovering self-building structures and strange alien creatures.
It's not yet clear where in the Mass Effect universe Andromeda will fit (aside from Andromeda, probably). The original trilogy of games were limited to the Milky Way, while Andromeda will let you "discover a new galaxy," so it sounds like it either takes place after or parallel to Commander Shepard's exploits. We'll know for sure when it releases next year.
