It looks like Level 5's Professor Layton series isn't just going to stay a trilogy after all. Subtitled "Majin no Fue", "The Devil's Flute" is the first title of a second trilogy that will be due sometime this autumn.

There's not much on the site just now besides the following:

A young man that prophesises the end of the world, Luke.
"The Legend of the Devil" that tells of a mysterious giant that will destroy the town.
When the "Devil's Flute" is blown, the giant appears...
What is its true identity? Is it a god? Or is it a demon?

I've yet to play the second and third games but, interactive riddles on a console aren't really my cup of tea. I think it has a great soundtrack and presentation though.