The music was composed by Deva and lyrics written by Agathiyan and Ponniyin Selvan. The film was initially titled as Nila Odi Vaa before it was named as Kadhal Kottai. Р”Р„gathiyan had asked Devayani to change her glamorous on screen image for the film, and Devayani duly agreed with the film becoming the start of several other similar roles for her. Post its success, he chose Ajith, actor from that film to play the leading role with Sivasakthi Pandian agreeing to produce the film. Agathiyan initially wanted to make his directorial debut with this subject since no producer were willing to produce the film, he made few films and earned his breakthrough with Vaanmathi. Agathiyan confirmed this in his interviews. The basic theme of the film was inspired from 'Puranaanooru' literature on the relationship between King Kopperum Chozhan and poet Pisirandhaiyar, though they never met but they developed a strong relationship until their deaths.

Sabitha Anand as Malliga, Kamali's sister.

As the train departs, in a turn of events, Suriya removes his shirt wherein Kamali notices it was her gifted sweater and finally unite, as Paneer and Jensi watches the pair and rejoices.

As Kamali plans to head home, depressed, Suriya assists her to board Nilgiri Express. At the end of the day, both gets refreshed at his place, while he dons her gifted sweater covered by his uniform. Pinning hopes, she boards the Suriya's autorickshaw, driven by him without knowing it him traces and searches for him desperately, wherever he lived. Upon arriving in Madras, which is experiencing severe monsoon, Kamali finds that Jensi and other hostel mates were out of station. Shekar, who initially dissuades Kamali's love finally gives in and allows her to Madras half-heartedly. Jeeva ( Raja), a wealthy businessman expresses his interest in marrying Kamali to Shekar, but Kamali excuses herself to consider her as prospective bride when she meets Jeeva in private and shares her unflinching love for Suriya, who even allows her to meet him for one last time. Unable to withstand the advances of Neya, Suriya quits the job gets sheltered by Paneer ( Thalaivasal Vijay), who arranges him an autorickshaw to engaged as driver.

Refusing a Job offer which would move Kamali to Singapore, making it difficult for her to find Suriya she moves back to her home in despair. In the meantime, unintentionally they both run over upon each other without knowing who they really were resulting in negative perception and misunderstanding. Her repeated attempts in gaining his love and affections fails as he staunch on his love for Kamali. Suriya is attracted and smitten by his boss Neya ( Heera Rajagopal). Kamali too moves for Madras to find a job for her and stays with her friend Jensi (Indhu). As Suriya shifts to Madras for work and stays with Siva ( Karan). They agree to love each other without meeting, as she sews and sends a gift pack containing a lotus embroidered woollen sweater for him to wear when they meet for real. Suriya ( Ajith Kumar) who is an orphan and care-free man, works in Jaipur finds the purse and sends it back to her, and a love develops through letters and phone calls. While visiting Madras, her purse is stolen and she fears she has lost her academic credentials. Kamali ( Devayani) lives with her sister, Malliga ( Sabitha Anand) and brother-in-law, Shekar ( Rajeev) in Kotagiri, and is searching for a job and lives with high hopes of getting married soon.

Kadhal tamil movie