There is a lengthy description over at Bioware’s Blog but here is a short excerpt that explains the basic premise of the DLC. Bioware and EA will no doubt be hoping to lure people back into Shepard’s story later this summer however with the release of the first single player DLC pack Leviathan.
After being pleasantly surprised by the high quality and addictive nature of Mass Effect 3’s multiplayer, not to mention all the free DLC support the game has enjoyed, I have not really felt the inclination to play the single player campaign since finishing my second run through.