Captain Sam Wyndham, former Scotland Yard detective. He was seriously wounded in France in the First World War. To forget the terrible memories of that war, he moved to Calcutta, joined the intelligence department of the police force. But Windham was unable to adapt to the new environment and was breaking down mentally. At this time, he was charged with the investigation of a mysterious murder. A high-ranking British officer was murdered. The murderer stuffed a paper ball over the corpse's mouth. It reads -- 'Quit India, or...! ' India is getting hot in the fight for independence, the British Empire is in turmoil! Against this backdrop, Wyndham and his two assistants, Inspector Digby and Indian-origin Sergeant Banerjee, set out to investigate the murder. Starting from the luxurious parlors of rich British businessmen, these three figures reached the dark opium den of Kolkata to unravel the mystery of the murder.