Kaaval translates to "Police" in Tamil. This film has nothing to do with police business, as much as it is about revenge and violence. There isn't much of a story, and someone is preaching to the audience in every second scene. There is one police officer who takes his job too seriously, and breaks into a monologue of "Police this, Police that, Police everything". What ensues is a childish game of cat and mouse, where gangsters die and policemen get suspended for violating human rights.
Vimal plays every character he has ever played, to the point where his presence in the poster already gives away the ending. The masala template of Song-Fight-Emotion-Climax where good guys win has been followed almost to a fault. The audience is just lost most of the time, and laughs at poor attempts at comedy because laughter is the only emotion they can muster at this point. Don't bother wasting precious resources to watch this movie. The sun is merciless in any case.