Mass Effect 3, with one focused on multiplayer and the other serving as "one final, sentimental journey with Commander Shepard and their squad," according to the press release.
The first batch of content, "Reckoning," is a free bundle of multiplayer DLC that'll be available for free when it lands this Tuesday, February 26. The pack adds new characters, weapons and item upgrades for use in multiplayer, though what any of those things are specifically remains to be seen.
"Citadel," meanwhile, is Mass Effect 3's last chunk of single-player DLC, arriving on March 5 for $14.99/1200 MS Points. The pack returns Shepard and crew to (where else) the Citadel, on a mission that will give players the "opportunity to reconnect with some of their favorite characters from all three of the Mass Effect games." Well, provided you didn't get them horribly murdered, we figure. You know what you did.