Maa Kasam is a 1985 Hindilanguage Indian feature film directed by Shibu Mitra, starring Mithun Chakraborty, Amjad Khan, Divya Rana, Kalpana Iyer, Ranjeet, Sharat Saxena and Pran.
Balwant returns to home after completing his sentence. He came to know that, the Thakur has a treasure map hidden in a diamond ring. He kills the Thakur, but unable to get the ring. He wanted to find the ring, but ends up killing his own. His dying wife, takes her young son, Dharma, and requests the Thakurain to lok after him as her own son. Balwant is again arrested and gets a long jail term. Now Dharma has grown as a hardworking and honest man under Thakurains care. Now Chakradhari, a con man makes life miserable for the people. At the same time Balwant completes his sentence and returns for the ring. Who possess the ring forms the climax.
Source: Wikipedia