Titled "Beneath the Ashes," the episode picks up after the main game, with protagonist Lara Croft exploring "never-before-seen" caverns underneath her ruined estate. Six new costumes and 125 gamerpoints worth of new achievements will be included as well.
The second episode, "Lara's Shadow," will follow on March 10, bringing "a new kind of playable character" to the game. Those that have played through the game can probably guess which character that'll be, as the pack's title pretty much gives it away.
No price point was provided for either pack, though GameStop will be selling a $20 bundle with tokens for both episodes, suggesting each will sell for 800 MS Points ($10). Combined, the two chapters are said to add roughly six hours to the game.
Since its mid-November release on PC, PlayStation 3, Xbox 360, Wii and Nintendo DS, Tomb Raider: Underworld has sold roughly 1.5 million units worldwide--a disappointing figure for publisher Eidos, which hoped the game would sell over 2 million units. The company subsequently laid off 30 employees from developer Crystal Dynamics.
Thanks to Luckyg for the tip.