The Bethesda Blog announces that development is complete on Dishonored, and Arkane's stealth/assassination game will be available for Windows, Xbox 360, and PlayStation 3 on October 9th in North America and October 12th in Europe. They celebrate the news with a giveaway of "an extremely limited" Overseer mask and a signed copy of the game. Here's a description from the Dishonored website:

You are the once-trusted bodyguard of the Empress. Framed for her murder and driven by revenge, you must become an infamous assassin, known only by the disturbing mask that has become your calling card.

As you navigate a world torn apart by plague and oppressed by a government armed with strange new technologies, the truth behind your betrayal is as murky as the waters surrounding the city.

The choices you make will determine the fate of the world, but no matter what happens your old life is gone forever.