Kochadaiiyaan opens with a prologue that tells us that the two kingdoms, Kottaipattinam and Kalingapuri, have been at war with one another for generations. We see a boy from Kottaipattinam, who is about to drown, being rescued and the boy, Rana, grows up to become a soldier in Kalingapuri. He earns the friendship of the prince Veera Mahendran, and is made the general of its army. He seeks the king's permission to attack their enemy nation but on the battlefield, Rana reveals himself to be the son of Kochadaiiyaan, the famed general of Kottaipattinam and admits that he enacted a drama to rescue the soldiers of his motherland, who were being held as slave labourers there. Rana is received with joy by his king and even gets him to marry the prince to his sister, but he also has an ulterior motive — to kill the king, who had unfairly sentenced his father to death.

Kochadaiiyaan succeeds not because of technology but because of the writing. The film is motion capture 3D computer-animated but the animation is primeval; both the motion capture and the texture of the visuals are closer to The Polar Express than Avatar or Tintin. The long shots aren't problematic but whenever the camera cuts to a close-up, we are drawn to the inanimate nature of the expressions. The characters feel like caricatures of the real-life actors we have known. The movements of the actors, too, are robotic (in dance numbers, it feels like the characters are doing yoga), and the detailing is far from perfect, especially for characters in the background.

There is also inconsistency in the animation. Some of the scenes seem to have sheen while in some the perspective fluctuates; there are times when a boulder looks as big as the man standing on it and blades of grass look like miniature paddy plants. But the sweeping camera work, the proficient voice over work by the actors, and the energetic background score compensate for these blemishes.

Once the plot kicks into gear, the animation takes a backseat and the narration starts to hold our attention. The songs and the stunts are woven into the story and do not stick out. Like any other Rajini movie, Kochadaiiyaan, too, worships its star. His character appears in almost every scene and there are fan-pleasing moments in the form of stylistic gestures and dialogues.

The story initially seems like a typical simplistic revenge fantasy (a son avenging his father's death) but as the plot progresses, we realize it is a bit more complex than that. The film actually ends by leaving its lead character in a moral dilemma. His family has served the king and protected him for generations but now, the son has acted otherwise. What fate does his action beget him? What happened to Rana's elder brother who has vanished mysteriously? Where is his friend who abdicated the throne to marry the girl he loved and chose to leave his kingdom? Will the enemy prince that Rana let live return? With such interesting questions, Soundarya has set up the knot for a deserving sequel.