Source
Bethesda's next title has been revealed - a first-person, stealth-based action game called Dishonored by Arx Fatalis creator Arkane StudiosStudio co-founder Raphael Colantonio is on board, as is Harvey Smith, one of the developers behind Deus Ex, and Viktor Antonov, the designer who created Half-Life 2's City 17.Dishonored is an open-ended adventure title that allows players to tackle missions in a number of different ways, from stealthily completing tasks to letting loose on hordes of enemy soldiers. How players decide to deal with problems will shape Dishonored's world.Update:The game is due for release on Xbox 360, PlayStation 3 and PC in 2012.
First details and screenshot
Not sure what to think of the screenshot, but sounds kind of like assassins creed but with magic, and steampunk.