Kannan(Prithvi) is in leage with his father(Manivannan) in duping the people in his village. He comes across Kausalya(Sruthi), a timid, schoolgoing Brahmin girl and falls for her immediately. From his grandfather he learns that Kausalya's mom is his father's sister and becomes even more determined to wed her. Kausalya begins to like him too but asks him to mend his ways before they can get married.

Kai Vandha Kalai is intended to be 2 things - a comedy and a debut for Prithvi. The flimsy story is simply an excuse for Pandiarajan to string together comic episodes and create situations that showcase the emoting, dancing and fighting skills of Prithvi. He might have succeeded in the latter but has failed pretty badly in the former. The entire film barely raises more than a few chuckles. Many of the episodes intended to raise laughs are silly and some(like Manivannan's attempts to get rid of his own father) are even disgusting. Even the ones with potential(like the visits Pandiarajan and Prithvi make to houses where someone has died) go on for so long that the humor is stretched real thin. So, as was the case with Jery , this is a failed comedy and that's the toughest kind of movie to sit through.

Movies typically tend to meander in the first half as they introduce characters and create issues. So its not terribly disappointing when Kai Vandha Kalai lays the foundation for a passable love story in the first half. It gets Prithvi and Sruthi together and through their family members, shows that its not going to be smooth sailing for their romance. It doesn't do much more than that but that's all that is expected.

For most movies, their screenplay gathers speed in the second half as they try to resolve those conflicts. Not so in the case of Kai Vandha Kalai, which simply stalls. Pandiarajan has no idea how to move the story along and so abandons it completely. Once Prithvi becomes Pandiarajan's assistant under the pretext of making an honest living, the movie turns into a series of episodes (that have no impact whatsoever on the story) revolving around their business. The running time is further padded with fights and an item number, that are all set up in a silly manner and simply confirm the paucity of ideas on Pandiarajan's part. Its only in the last five minutes or so that the movie remembers that it has a love story to resolve and naturally, the result is a lacklustre climax.

Aanpaavam was probably Pandiarajan's biggest hit in his career and is the film with which people still identify him. So he has naturally tried to milk as much as he can from that film by using actors, locations and background music from that film. There is a lot of nostalgia associated with the film, one of the best comedies in Tamil cinema, and so it is fun seeing the references to it. But unfortunately, Pandiarajan has not played it straight. He uses actors like Pandian, Seetha and Revathi in roles meant to remind us of Aanpaavam but doesn't go all the way. So while he was Pandian's younger brother in that film, he is Seetha's younger brother in this. This leads to a little confusion and also a nagging feeling that he was too lazy to think a little more and come up with a story that could actually serve as a sequel to Aanpaavam.

Prithvi looks too young to be a hero. But apart from that, he seems to have been prepped well enough since he fights and dances impressively. Sruthi, the child artiste from Azhagi , is definitely too young to be a heroine. They have tried to make her look older through makeup and the results are not very flattering. Pandiarajan gamely tries to make his jokes work while Seetha ends up looking the most natural of the performers. A number of comedians like Senthil, Janakaraj and 'Venniraadai' Moorthy have cameos.