Kalyani (Ranjini) is the daughter of a wealthy NRI Ramachandra Menon (Poornam Vishwanathan) who resides in the United States. Kalyani, brought up in Chennai by her father's friend Kaimal (Nedumudi Venu), falls in love with another man and decides to marry against the wishes of her father. When her boyfriend finds out that she will be disinherited, he ditches her at the altar.

After a short while her father decides to retract his disapproval and spend a fortnight's vacation with his daughter and son-in-law in his estate near a tribal community where Menon is the chief. Because her father is already ill and because this may be his last vacation, Kalyani and Kaimal want to make it as happy for him as possible. They decide to conceal the fact that her boyfriend dumped her.

Kaimal hires Vishnu (Mohanlal) to play the part of the husband for a fortnight. Meanwhile, Kalyani's cousin Bhaskaran Nambiar (Sreenivasan) who is the caretaker of the estate was expected to inherit Menon's estate and property when Kalyani was disinherited, is determined not to let go without a fight. He knows that Vishnu is not Kalyani's boyfriend and makes various botched attempts to prove this.

Initially Vishnu and Kalyani do not get along and keep bickering. But as time passes, she develops an affection towards Vishnu and hopes to marry him for real. A couple of days after they have a mysterious visitor (Soman) who claims to be a relative of Vishnu.

Finally it is revealed that Vishnu is actually an escaped convict from jail who is sentenced to death and the visitor turns out to be the prison warden. Vishnu's past is shown in flashback and he was a freelance photographer who was married to a woman named Revathy (Lizy Priyadarshan), a mute dancer. They also had a child. Vishnu discovers that a man was visiting his wife when he was not around and begins to suspect her. Coming home one day he finds the man there and tries to attack him. Revathy dies in the scuffle, Vishnu discovers that the man is actually her brother who is a naxalite. He tells Kalyani that he escaped prison to make money for the surgery of his child.

On the last night of Vishnu's stay at the house, he asks Jail Warden, is it possible for him to live, as he started to like life again. The warden replies that it is too late, which further breaks Vishnu down. After a happy fortnight, Kalyani's father returns to the US. The final scene shows the warden taking Vishnu to jail, with Kalyani watching him leave, where his execution awaits him, indicating the film ends with Vishnu's tragic death.

The film's songs were composed by Kannur Rajan and lyrics penned by Shibu Chakravarthy. M. G. Sreekumar sang most of the songs in the film. Carnatic music singer Neyyattinkara Vasudevan was a guest singer. The classical Krithis like "Nagumo" and "Swaminatha" featured in the film gained a mass popularity. Playback singer Sujatha Mohan also sang in the film, marking her return after years of sabbatical. Mohanlal sang two songs "Kaadumi Naadumellam" and "Aey Monnu".

• P. K. R. Pillai of Shirdi Sai Creations started 2 films together, Chithram and Nair Saab, but as he faced financial issues, he sold Nair Saab to Basheer of Liberty Productions and completed Chithram.
• The film ran for 405 days in theatres with 369 regular shows in three theatres in three districts and with 36 noon shows.