1920: Evil Returns (movie, 2012)

This story revolves around a famous poet who meets a woman who is in trouble. In order to treat her, he takes her to Shimla in a big hospital, but soon that woman gets possessed by devil and goes out of control. Now the question remains that what is the relation that poet shares with her which compelled him to go to any extent to save her, why she was possessed by devil and who is the devil.