Sajre Phull attempts to sensitise children to the evils of the feudal system while explaining options like cooperative farming to optimize a farmer’s efforts. The film also busts the belief in evil spirits and other social misconceptions prevailing in the society.
Suvarna (Sohan Lal Khanna) is a hardworking peasant, who believes in collective farming. Co-operative farming, to him, is the best method to achieve maximum production. He inspires his co-peasants to do the same. Village Chaudhary Amar Singh (Suresh Sagar) and his wife Lajo (Manorma) detest Suvarna’s idea of farmers working in collaboration. Hence they conspire against Suvarna and falsely implicate him. One day Suvarna is away with his family, celebrating a festival with song and dance in the fields. Lajo and Chaudhary execute their plan by hiding their ornaments and jewellery in Suvarna’s house. They report the supposed theft of jewellery to the police. Police inspector Raza Murad reaches the venue and asks Suvarna to accompany him for the search of his house in view of the reported theft. The police recover the stolen goods from Suvarna’s house and he is arrested. His wife Neena Cheema and his son Pappu (Master Anoop Tiwari) plead non-guilty. However, their pleas are totally ignored by Thanedar, and Suvarna is sent to jail.
In the same village resides a 12-year-old girl, Munni (Vidisha Chaterjee). She is a friend of Suvarna’s son, Pappu. Munniearns her livelihood by picking up burnt coal pieces from the railway tracks and sellingthese to Parma, a sweetmeat seller in the village.In this way she is able to feed her blind mother (Laj Bedi) and provide fodder to her two oxen Kundan and Chandan. She is liked by the lonely Station Master (Bhag Singh) who is always ready to help her and even provides her a small job of water-girl at the station after she loses the coal picking job as steam engine is converted to diesel locomotive. He asks Pappu to teach Munni in his leisure time.
A distraught Pappu and Munni plan to gather evidence against Lajo and Chaudhary so that innocent Suvarna can be released from jail. Both the children know that Lajo is very superstitious. Hence, they make use of her weakness and trap her in their plan. They arrange a play of ghosts to frighten Lajo. The village postman (Meher Mittal), a kind-hearted person, also helps the children by playing the king of ghosts and the magician to bring the real culprit out into the open. Lajo and Chaudhary admit to their crime and the truth triumphs. They are taken into police custody and Suvarna is released from jail.