'Shapath Nilam' is the story of Bengal's revolutionary Dinesh Majumdar. When India was under the British rule young men like Dinesh resorted to revolutionary means to fight them. The film traces the life and activities of Dinesh who joined Jugantar party under Rashik Das's leadership and tried to kill torturous and ruthless policeman Tigard but fails. He is imprisoned but escapes jail to start the fight again. Gradually most of the revolutionaries either get caught or killed. Dinesh also gets caught and dies a martyr's death.