A famous film actor Arindam (Uttam Kumar), a star of Bengali films, has been invited to the capital to receive a prestigious award. As all the flights are booked, he is forced to travel by a train from Calcutta to New Delhi. He is in a foul mood as the morning's papers are filled with his being involved in an altercation and his latest film is slated to become his first flop.In the restaurant car, he meets Aditi (Sharmila Tagore), a young journalist who edits a serious women's magazines. Filled with contempt for the likes of him, she secretly plans to interview him because she thinks it would make a saleable 'copy'. It soon leads to him pouring out his life history. Aditi takes notes, surreptitiously. Critical of the star, she interrogates him and the star ends up re-examining his life. In a series of conversations with Aditi, he reveals his past and guilt.

He talks about Shankarda, his mentor, taking us back to his early youth. His selling out to films and giving up theatre against the wishes of his old teacher... His first day's shoot, and he being snubbed by a successful actor Mukunda Lahiri. A few years later Mukunda Lahiri, now a forgotten actor after a series of flops, comes to him to beg for a small part. He rejects the ageing actor in revenge. His taking refuge in alcohol. And his refusing to help a friend in politics.

In the fag end of the train journey, he is drunk and contemplates suicide. He asks the conductor to fetch Aditi. He begins to confess an affair with a married woman. But Aditi stops him. It was an affair with a heartless and ambitious Promila, which ended in a brawl with her husband.

As the star re-lives and examines his life with Aditi, a bond develops between them. Aditi realises that in spite of his fame and success, Arindam is a lonely man, and needs her sympathy and understanding. Out of respect for his frank confession, she chooses to suppress the story and tears up the notes she has written. She lets the hero preserve his public image.

Based on his second original screenplay, Nayak is not among his best, but is a delight to watch and far superior to average cinema. He cast Uttam Kumar in the title role of the hero (star). Uttam Kumar was a star of the commercial cinema in Bengal at that time. The film takes place in a period of twenty-four hours on a train. The hero's life is revealed through a series of flashbacks and dreams. The film explores the psychology of the star and his admirers.

The best part of the film lies in its form. The train journey becomes a metaphor for the star's life. The best scenes involve the star's interaction with fellow passengers, a slice of affluent Bengali society.

Both Uttam Kumar as the star and Sharmila Tagore as the young journalist gave superb performances.