Dark Souls II will be a direct sequel to Dark Souls I, meaning the game will continue the story of the first game. In the new Dark Souls II you won't return to Lordran but to a whole new world. Unfortunately there are no more information about this new world, details will be showed in the upcoming weeks and months.

 Dark Souls 2 were officially announced several days ago. The EDGE magazine had their eyes on an exclusive 10 minutes long demo version of  Dark Souls II and especially the graphics are way better in comparison to the first game. The developer have also improved the covenant system, added a moral system to the hardcore role playing game.
Another detail were revealed: The work for the game started in september, 2011 and they're 25% finished. The sad part is that it's unlikely the game will be released in 2013.

Source: edge-online.com