Thor: The Dark World screenplay is written by Christopher Yost, Christopher Markus and Stephen McFeely whereas story is written by Don Payne. Movie is set to release on October 31, 2013 in Australia whereas release date in India and Canada is not out yet. You can check out Thor: The Dark World DVD release date here.
UK/Ireland: October 30, 2013
Australia/Denmark/New Zealand/Netherlands: October 31, 2013
USA: November 8, 2013
Canada/India: November 8, 2013
Plot: Thor has to make ultimate sacrifice while saving nine realms and Jane Foster from enemies that even Odin and Asgard cannot overcome.