This is a movie you'll have to stick with beyond the first twenty minutes or so because the opening seems very disjointed. The principal character, Arun Kumar (Vishnu Vishal),is trying to negotiate a film deal as an assistant director, and suddenly has to do an about face and accept a position as a sub-inspector with the local police. He gets in trouble with his brother-in-law for forging his niece Ammu's (Abhirami) report card, and in an effort to save face with Annu's teacher (Amala Paul),pays for the objects her mute daughter shoplifted at a neighborhood store. It all seems rather confusing until the story line settles into an investigation of serial murders targeting teenage school girls. That's when Arun rises to the occasion and uses his extensive background of studying vicious crimes to solve a mystery that's continually thwarted by an overbearing police captain (Suzane George) who almost never sees things his way.

The clever screenwriting reaches a level of complexity when it reveals a circumstance behind the third missing murder victim named Meera. By chance, Meera had a recording device in her hearing aid to help her with her speech, and it provides a clue to the type of music associated with the serial killer. But even that clue leads to an unusual twist that you might see coming, later confirmed when it's revealed that the suspected murderer had a son with an aging disease that left him disfigured and the brunt of cruel derision during his youth.

The relentless pace in the latter part of the movie is supported by a tension filled musical score that keeps one's nerves on edge, and even if you've seen dozens of crime movies that hinge on a suspenseful climax, this film will set those apart with a stylistic portrayal of the serial killer as a skilled magician using his talent to confound Arun in his attempt to save a potential fifth victim. The action becomes so dizzying that you won't be able to figure out how the sub-inspector dealt a final blow to the killer with an iron rod. You can replay it any number of times you want and it will still leave you baffled, though one's sense of relief that the serial killer has been stopped will overcome any momentary confusion. I saw this film under the title "Raatchasan", with it's English sub-title 'Demon', and after witnessing the brutal manner in which the young victims were killed, you'll find that translation entirely fitting.

"Ratsasan" is a Crime - Thriller movie in which we watch a sub-inspector investigating a series of murders and since the victims are only school girls he understands that he has to do with a mysterious serial killer. He has to be fast because many other murders will occur.

I have to admit that I did not know what to expect from this movie but I was surprised by it since it was very good. It had an interesting plot, full of suspense and some plot twists that I did not expect. The direction which was made by Ram Kumar who is also the writer, it was very good and he combined very well action and suspense with drama and he did not make his movie predictable something that would ruined it. Vishnu Vishal who played as Arun and Amala Paul who played as Viji, they were very good and they succeeded on making us relate to their characters. In conclusion, I have to say that "Ratsasan" is a very interesting movie with a well-written script and I highly recommend it to everyone.

With the usual cinematic detective tropes but a haunting background score and arresting overall filmmaking that will keep you on the edge of your seat, Ratsasan (Monster) excels as a psychological thriller and police procedural that traces an unknown psycho serial killer. TN.