Anbarasu(Madhavan), who likes to be referred to as A.Ars, is a high-flying, ad-filmmaker working for a multinational company. On assignment scouting locations in Bhubaneshwar just four days before his wedding, he is stranded at the airport as Bhubaneshwar is lashed by heavy rains and flood. With no place to go, he finds himself in the company of Nallasivam(Kamalahassan), who seemingly has an answer for every question and an uncanny knack for irritating Anbarasu. Together, the duo set off in the direction of Chennai and on the trip, Anbarasu finds himself learning a lot about love and life.

"For one who believes in God, God is love while for an atheist, Love is God". That line by Kamal sums up the theme of the movie. Through a series of incidents in the life of one man who has been scarred both physically and mentally but come out of it an even better man, the movie coveys its message in a strong manner.

Anbe Sivam straddles several genres and surprisingly, the most prominent among them are themes rarely attempted in Tamil cinema. It can be seen as a road movie, a movie on male bonding, a socially conscious, message oriented film or a comedy. It has lofty messages and large human tragedies. But there are also times when it raises laughter relying purely on slapstick. The movie's biggest success lies in the effortless ease with which it moves in and out of these disparate themes. The varying emotions never intrude on each other and the movie mixes comedy and sentiments in what seems to be just the right amounts.

While the movie as a whole juggles several themes, the same characteristic of merging varying emotions is seen on a smaller scale in several individual scenes too. The dialogs at several places skillfully twist into comedy and bring forth laughter at the edge of a seemingly sentimental scene. It is difficult to turn a sentimental scene into a comic one without seeming callous but the movie manages the transition admirably. Two notable examples are Madhavan's enthusiastic appeal to donate blood after seeing the injured boy and his response to Kamal when asked why he had never revealed his affection for him before. But Yugi Sethu's antics at the train crash site is one scene that doesn't gel and doesn't fit in with the huge tragedy.

Kamal's flashback turns out to be weakest part of the film. While the communism slant adds something new, the romance itself is too brief to make an impact. Nasser, as the hard-hearted manager unwilling to increase his worker's wages, and Kiran, as his daughter falling for and helping one of the workers, come off as weak, two-dimensional characters seen several times before. The outburst of Kamal's comrade, after realizing she has lost in love, is the one bright spot in this segment. It is a wonderful scene that adeptly invokes laughter through the way she voices her disappointment. The movie also lacks a powerful climax that would have transformed it from a good movie to a great movie. The climax is too low-key, convenient and lacks a powerful punch.

Kamal adds another memorable character to his bag of roles. His make-up, body language and dialog delivery combine to transform the actor into Nallasivam The scarred face, glasses and badly set teeth are a marvel and small acts like the facial twitching leave us amazed at his dedication to his craft and attention to detail. Madhavan is the surprise package here, matching Kamal step for step. He effortlessly makes us laugh at his irritation with Kamal and is convincing in portraying the changes he goes through too. A deglamorized Kiran is a lot more pleasing to look at compared to her garish, over made up looks in Villan while Nasser does what he can with his stereotyped character. While Vidyasagar disappoints, the art director makes us sit up and take notice. Whether the flooded railway station in Bhubaneshwar or the site of the train crash, the sites are convincing.