The film starts with Kathir( Surya) planting bombs on a running oil tanker train, and cuts into a flash backs which starts 6 months back. We see Kathir as a farmer creating a green revolution using only natural resources for framing. But we also see him planning a strike in nearby military base filled with chemical weapons. Parallel to this we see an assassination threat against the Prime Minister Chandrakant Varma (Mohanlal) being contained by the secret service. We then come to know that Kathir is a secret agent working closely under the government. The Prime minister appoints Kathir as his personal body guard as the threats have been consistent. But Tragedy strikes when the Prime minister visits Kashmir and dies in a bomb blast. Worst even Kathir becomes one of the suspect. How Kathir eliminates the terrorists group behind this is the rest of the story.
Director KV Anand keeps us quiet engaged with lot of things in the first half, though this creates various paths in the story this also creates frustration as it leads to no where. Forced songs sequences irritates and music doesn’t merge with the film at all. Surya though has performed to his best to the character, but is finally left behind as the story and screenplay fails miserably in the second half. Though some key scenes bring out some interest to audience, the film collapses with too many things to follow and becomes a big mess in the climax. Sayyeshaa just manages through in the film, and one wonders why Arya was casted in the film at all. Kaapan is over cooked with lot of things and ends undigested . I give it 4/10