The film starts with a very anxious Aditya looking for Suhani on late night trains, stations and everywhere else with help of his friends. She has gone missing on her way to university. Suhani and Adityas first meeting is shown to us as a flash back. They met a friends wedding where Aditya tries to flirt with her but she brushes him off. Few days later they spot each other on the trains on their way to university. Soon they start glancing at each other and both their friends tease them that they are in love. Suhani insists that she does not believe in love and romance, but Aditya is relentless and eventually she admits that she too is attracted to him. All seems set for a big wedding, but their dreams of a life together are destroyed when their parents argue and are at loggerheads over social status during their first meeting. The young couple decide to keep away from each other and not take the relationship forward anymore, but fail miserably - they both miss each other and are deeply in love. Suhani goes away from town for a medical camp and Aditya pines to see her, he leaves his house much to his familys dismay, he goes to find her. They finally embrace and reunite. They decide to break all the rules and get married in secret. Suhani returns to her house and they keep their marriage a secret for a while. Till one day, when her family find out and kick her out of the house - as her relevation had broken a prospective engagement of her older sister. Aditya picks her up as her dad throws her out of the house, and curses the pair for their betrayal. Aditya and Suhani move into dilapidated apartment and begin their happy married life. However, reality sets in and arguments start between them over small matters. They go to a festival with Adityas friends and Suhani gets jealous seeing Aditya dancing with someone.She leaves meeting her sister Suhani has a road accident on her way home and goes into a coma while Aditya is searching desperately all over to find her. Finally he finds her in the hospital fighting death and then realises how much he really loves her.

Soundtrack

There are 9 songs composed by A. R. Rahman and lyrics by Gulzar. A. R. Rahman re-used most of his compositions from the Tamil soundtrack of Alaipayuthey, with the exception of two songs, Mere Yaar Mila De and Naina Milaike which replaced their Tamil counterparts Evano Oruvan and Alaipayuthey. The soundtrack turned out to be one of the strong points of the film.

Song	Artist[s]
Saathiya	Sonu Nigam
Chalka Chalka Re	Richa Sharma, Mahalaxmi Iyer, Vaishali, Shoma
Aye Udi Udi Udi	Adnan Sami
Chupke Se	Sadhana Sargam, Murtaza Khan, Qadir Khan
O Humdum Suniyo Re	Kunal Ganjawala, KK, Shaan, Pravin Mani
Mere Yaar Mila De	A. R. Rahman
Naina Milaike	Sadhana Sargam, Madhushree
Mangalyam	KK, Shaan, Kunal Ganjawala, Srinivas
Chori Pe Chori	Asha Bhosle, Karthik, Blaaze

Awards

;Filmfare Awards Saathiya won six awards at the Filmfare Awards. * Critics Award Best Performance - Rani Mukerji * Best Music Director - A.R. Rahman * Best Lyrics - Gulzar * Best Male Playback - Sonu Nigam for "Saathiya" * Best Dialogue - Gulzar * Best Screenplay - Mani Ratnam ;Zee Cine Awards * Zee Cine Award for Best Music Director - A R Rahman * Zee Cine Award for Best Lyricist - Gulzar * Zee Cine Award Best Playback Singer- Male - Sonu Nigam * Best Sound - Robert Taylor ;IIFA * IIFA Best Music Director Award - A R Rahman * IIFA Best Male Playback Award - Sonu Nigam ;MTV Immies * Best Composer - A R Rahman * Best Lyrics: Gulzar * Best Singer [Male] - Sonu Nigam ;Bollywood Music Awards * Best Male Singer - Sonu Nigam ;Bollywood Movie Awards * Best Actress [Critics Award] - Rani Mukherjee * Best Music Director - A. R. Rahman