Vealvi is the story of a young girl's revenge. How she fights the system on her own terms and conditions forms the crux of the story.

Thulasi, an aspiring lawyer, is a person who does not accept injustice and questions anything she feels is wrong. She is in love with Chandru, a happy-go-lucky guy, who takes life as it comes. He is not carried away by right and wrong. This young couple goes about their lives planning for a happy future. But things take a drastic turn and their lives turns completely topsy-turvy...

Being a person who does not like wrong actions, she takes against three of her college seniors, men involved in all sorts of anti-social activities. She keeps on crossing swords with them and the trio decides to teach her a lesson. They attack her and gang-rape her. 

Scarred by the incident, Thulasi somehow comes to grips with the situation. She expects Chandru to be her support during this difficult time, but he refuses to accept her, a woman who has been used and abused by not one, but three men. Saddened and hurt, Thulasi decides to take matters into her own hands.

Rejected by her lover, she goes back to the three men who raped her and agrees to be their keep. But she uses this proximity with them to extract revenge for the abuse she was subjected to. Giving them brutal and different deaths, she also gets in touch with her ex-lover Chandru under the pretext of some favour. Chandru is now all set to get married to another girl, but agrees to help her for old times' sake. But when he meets her, she kidnaps him and punishes him too.

What is the punishment she give Chandru? How was the death given to her rapists different? Is Thulasi punished by the law? All these questions will be answered when you watch the movie.

Vealvi, with a novel concept, is the debut venture of software engineer-turned-director Jeans. The music and camera work are good. The second half of the movie, especially the climax, is interesting.