Nermai (1985)

Raja, a reckless college student and son of a smuggler, constantly clashes with Radha, the sister of his principled professor, Gowrishankar. When his father begs the professor to reform him, Raja resists at first but gradually changes his ways—and falls for Radha. As Raja and Gowrishankar try to lead honest lives, dangerous criminals from the past threaten their peace, forcing the two to unite against a common enemy.