Puthiya Niyamam is the social thriller which stars Mammootty and Nayantara in the lead roles. The movie is written and directed by AK Sajan. Puthiya Niyamam is produced by P Venugopal and Geo Abraham, under the banner VG Films. Adv. Louis Pothan and Vasuki Iyer are an inter-caste couple. They are blessed with a daughter named Chintha. Louis is a leading advocate, film critic, and social activist. Vasuki, on the other hand, is a Kathakali artist.Even though they had a love marriage, Louis and Vasuki's ideologies about life are different; which cause frequent rifts between them. An unexpected incident affects Louis and Vasuki's peaceful life and what happens to them and their relationship forms the crux of the story.As usual, Mammootty brilliantly depicts Adv. Louis Pothan, which undoubtedly is one of the best roles of his career in the recent past. His exceptional chemistry with Nayantara is a treat to watch. Nayantara delivers her career best performance as Vasuki Iyer. The actress just nailed it with her extraordinary acting skills. A great applause for her decision to dub in her own voice. Pradeep Kottayam, Rachana Narayanankutty, and Aju Varghese score with their significant roles. Sheelu Abraham is okay in the role of a rough and tough cop. SN Swamy surprises with his first ever on-screen appearance.AK Sajan, who has scripted and directed the movie, proves that he is one of the best writers in town. He has grown as a film-maker as well. The director has done complete justice to his brilliantly-written script. The movie is engaging from the beginning till the end, even though most of the scenes are restricted to the lead characters. But the comical sequences in the first half fails to entertain. The fantastic climax deserves a huge round of applause.Roby Varghese Raj makes a decent debut as the cinematographer of the movie. Roby's visualization creates the perfect backdrop for the movie, which is a crime thriller wrapped in a family story. Vivek Harshan scores again with his perfect editing skills.Vinu Thomas's songs are okay, but fails to make a mark. Gopi Sundar scores with his extraordinary background score; but still, is repetitive at certain points.A perfect thriller in the backdrop of a family story, with some outstanding performances.