Aag Se Khelenge (1989)

Police Inspector Shekhar Kapoor's only mission in life is to end the atrocities of underworld don Zaka and his son Shaka. In the course of his investigations he bumps into small-time criminal Johnny. But Johnny reveals that he is actually Police Inspector Ravi Saxena, a cop from Delhi, and that he has sneaked into Zaka's team in the guise of Johnny only to destroy them. Shekhar and Johnny decide to work together on their common mission. However, tables turn when Shekhar discovers from his office in Delhi that Inspector Ravi was killed six months ago.