Araviarasu (Vijaykanth) is a criminologist working as the chief instructor at the police training college. He uses his brains and brawn to catch criminals and has a passion for his job. Arivu is happily married to Aarthy (Navneet Kaur) after some enjoyable courtship and a song. Meanwhile top scientists and entrepreneurs get murdered in the city, by ordinary people like a student, a poor graduate girl, a milkman.

The top echelon of the police force is baffled by this murder spree. Suddenly Arivu is asked to investigate the matter as a top cop and his brother-in-law Manoj (Biju Menon) disappears in mid air as he is on his way from Mumbai to Chennai.

The sharp brain of Arivu leads him to Chandru (Rahul Dev), a guy who is killing off top 'brain trust' of future India using innocent people to murder them. However Chandru escapes to Canada when the super cop is just about to close in on him.

Not to be discouraged our hero in hot pursuit goes to Toronto, to catch the kingpin behind the operations. In Toronto (everybody speaks Tamil!) he is assisted by a sexy undercover Royal Canadian Police agent Lara ( Seril Brindo).

Together they unearth a plot to destabilize India with their "operation brain dead" plan where a foreign force jealous of India becoming a world leader wants to kill all scientists and entrepreneurs.

The bad guys are led by Martin (no explanation is given how cop Manoj and Martin look like twins? Maybe the bad guy did a face-off with the good guy?) The rest of the film is how our hero brings back Martin to Chennai and also uncovers another diabolical plot to destabilize the country.

The film has everything packaged as masala entertainment, and for a change Vijaykanth is engaging and enjoyable. There are just two songs in the film, by Srikanth Deva to show Navneet's and Seril's glamour. Biju Menon as bad guy is promising, while Rahul Dev looks anemic.

Thank god there is no irritating comedy track.

For the undemanding masala fan, Arasangam is worth a look, when you compare it with the recent crop of over hyped super hero films that failed to deliver.