I don't want to give away too much that it spoils it, but it's the story of a young man who becomes an orphan in Paris between the World Wars.
http://www.imdb.com/title/tt0970179/
A great effort from all the cast, the main characters Hugo and Isabelle were fantastic played by Asa Butterfield and Chloe Grace Morantz and I was even surprised by Sascha Baron Cohen who while did do some of his more typical funny man schtick, yet later showed surprising acting ability and sensitivity.
Great supporting parts too by Jude Law, Christopher Lee, Emily Mortimer, Helen McCrory and many others. Ben Kingsley, of course, is still a master of his craft.
Well worth the price of the ticket, if it doesn't win several Oscars, I'll be very disappointed.