The characters that Mammootty and Nayanthara essays in the movie 'Puthiya Niyamam' directed by A.K. Sajan will be at loggerheads most of the times. The characters Louis Pothen and Vasuki are diametrically opposite personalities. While Louis is an easy going advocate, who is also a film critic, with a leaning towards the leftist ideology, Vasuki is the exact opposite.

Vasuki is a very peppy person and this is what attracted Nayanthara to do her second consecutive Malayalam film this year. Vasuki's and Louis Pothen's inter-caste marriage and the problems that comes in their midst forms the crux of the movie.