Kannukkul Nilavu

The film starts with Gautham Prabhakar searching all around Pondicherry in vain for a girl named Gayathri. He encounters a group of friends led by Hema and asks for their help in locating Gayathri, who appears to be his lover. The group members are initially hostile to Gautham but eventually decide to help him after he pursues them aggressively, and Hema realises that he may be suffering from a neurological condition resulting in amnesia and delusions. Hema's father Dr. Rajashekar is a psychiatrist who discovers Gautham's real condition and the dangers it poses.

It is revealed that Gautham was actually a musicologist. About six months earlier, he had travelled to a hill resort in Tamil Nadu for his research on musical patterns in the sounds of nature. While on that trip, he encountered three men - Prakash, Soundar, and Shanmugam - who all hailed from Pondicherry. Gayathri was a local girl who was teased frequently by the three men. She regularly ran up to Gautham to seek refuge from the men's pursuits. Then, one day, the three men got drunk and began molesting Gayathri. Hearing her screams, Gautham and his friend Balaji attempted to rescue Gayathri. In the ensuing fight, Balaji's knee was struck with an axe, Gayathri dropped unconscious, and Gautham was hit hard on the head with the blunt end of the axe. The way Gautham remembers it is that the three men had molested and murdered Gayathri and then had left Gautham for dead after striking him on the head. Gautham, in his hypnotic state, swears furiously to Rajashekar that he will avenge Gayathri's murder by capturing and killing the three men responsible. As it is revealed later in the film, Gayathri had not died but had merely passed out.

Rajasekhar explains to Hema and her friends why Gautham viewed Gayathri as his lover in his delusional state, even though she actually had no relationship with him and he was merely trying to be a Good Samaritan. He also explains that if Gautham were treated and his memories brought back, then it could potentially create a new Gautham, a violent and aggressive one, who goes on a killing spree. Unable to decide on the next step forward, on Hema's suggestion, they decide to delay any action until Gautham's mother arrives from Malaysia. It is revealed through intermittent scenes that the mother, having not had contact with her son in the last six months, is already out of her home, searching desperately for her son in India.

Until the mother arrived, the kind Hema took care of Gautham. Gautham, for unknown reasons, becomes fond of Hema and believes deeply that she is the only person who can help him. In return, Hema also begins to develop feelings of affection and love towards Gautham. Hema even wonders if it would be possible to bring Gautham back to normal by showering him with enough care and affection that he forgets about Gayathri altogether. This strategy fails, as once the mother arrives, Gautham's memories come flooding back to him, and he turns into a ruthless revenge-seeker, terrorising both his mother and Hema and swearing to kill the three men who had supposedly murdered Gayathri.

The remainder of the film is about how Gautham's mother and Hema put up with the new villainous Gautham, while Rajashekar devises and implements an ingenious plan to cure him. Rajashekar manages to contact the three men, who reveal the truth: Gayathri was still alive. The three men are innocent, and the only terrible mistake they made was drunkenly striking Gautham on the head, resulting in this whole mess. While Gautham manages to capture Prakash and Soundar in revenge, Rajashekar and Shanmugam successfully trick him into entering Gayathri's current home by giving him chase. Gautham is initially dumbstruck at seeing Gayathri still alive, but reality eventually sinks in, and he is cured completely. He apologises to his mother, Shanmugam, and Hema for his torturous acts; reveals the location where he held the other two men captive; and profusely thanks Rajashekar and Hema for their efforts. Hema looks on sadly, wondering if this is the last she will see of Gautham. Rajashekar senses this and gives a non-verbal consent for Gautham to take his daughter with him. Hema is overjoyed, and the two, along with Gautham's mother, drive back.

Mohan Natarajan brought back together the team of the successful 1997 film Kadhalukku Mariyadhai in director Fazil and leading pair Vijay and Shalini with the venture. Filming began in July 1999, after Vijay eventually completed the shooting for his previous romantic comedy Minsara Kanna (1999). Anandakuttan was signed on to handle the camera and Ilaiyaraja to compose the music, while K. R. Gowrishankar and T. R. Sekar took charge of the editing, while the art direction was handled by Mani Suchitra.^[3] The shooting of the film took place in cities around Tamil Nadu and Kerala.^[4]

The soundtrack was composed by Ilaiyaraaja, while the lyrics were written by Palani Bharathi.^[5][6]