There was a lot of buzz this week that "Monster" and "The Killing" pilot director Patty Jenkins is the top candidate to direct "Thor 2."  Marvel Studios has already dated the film for July 26, 2013 and while their may not be a completed screenplay yet (to public knowledge) that doesn't mean Marvel hasn't figured out the storyline.  Marvel Studios president Kevin Fiege recently spoke to EW about it and had this to say about the sequel.

Fiege noted, "[This will] primarily be the journey of [Thor], of he and Jane Foster (Natalie Portman) and how the new dynamic with his father (Odin, aka Anthony Hopkins) is working out, as well as what are the broader stakes for The Nine Worlds." 

The Nine worlds that were depicted in Kenneth Branagh's May blockbuster "Thor" included iAsgard (Thor's home), Migard (Earth) and Jotunheim (home of the Frost Giants). In the comic books, the other worlds included Alfheim (home of the light elves), Hel (land of the dead ruled by the gorgeous but complicated Hela), Muspelheim (home of demons), Nidavellir (home of the dwarves), Svartalfheim (home of the dark elves) and Vanaheim (home of the Vanir, a sister race of the Asgardians).

If Jane Foster is returning as Fiege mentioned one would assume that means recent Oscar winner Portman is as well.  Marvel, however, is never afraid of recasting a role and if Portman wants to bow out they obviously realize the franchise would survive without her.