Pratidwandi (English: The Adversary, Siddharta and the City) is a 1970 Indian Bengali drama film written and directed by Satyajit Ray based on the novel by Sunil Gangopadhyay. It is the first part of the Calcutta trilogy. Pratidwandi tells the story of Siddharta, an educated middle-class man caught up in the turmoil of social unrest. Corruption and unemployment are rampant, and Siddhartha cannot align himself with either his revolutionary activist brother or his career-oriented sister. The film is known for experimenting with techniques such as photo-negative flashbacks.