Vaanam Vasappadum movie tells a young lawyer falls in love with Poongothai, daughter of a businessman Vijayakumar. Vijayakumar ends up in prison for running a Multi-Level Marketing trade. Karthik brings Poongothai to his house and seeks permission from his father Nasser, a speech impaired person and his mother Revathy. They eventually get married.
One night, after their car breakdowns, Karthik and Poongathai take a bus to reach home. But eventually misses her in the bus and she fall in the hands of a group of teenagers, who take to drinking and womanizing. Poongothai falls in their hands and they leave her in a dustbin with her hands tied after raping her.
The rest is about how Poongthai faces trial and does she gets justice for the brutal act inflicted upon her.