Kasu (2006)

Karan (Rahman) arrives in Kerala with his best friend Sandy (Charle) to meet the businessman Dileep (Rizabawa). At his office, the employees tell them that Dileep is abroad and the two friends decide to stay in Kerala until his return. Karan then comes across Prarthana (Sangeetha) on multiple occasions and they eventually fall in love with each other. Upon his return, Karan meets Dileep and Dileep refuses to help him. Karan comes to know that Prarthana is none other than Dileep's sister. Dileep proposes Karan a deal: either Karan marries his sister without any dowry or Karan takes a huge sum to let go of his sister. Karan surprisingly accepts the money thus breaking the heart of Prarthana. In a flashback, Karan lived with his mentor Vishwanathan (Poornam Vishwanathan) and his daughter Thulasi (Rajashree). At Thulasi's engagement, the groom's family asked for a huge sum of money and Vishwanathan reluctantly accepted. Vishwanathan planned to withdraw a property case in Kerala and to take the money so he requested Karan to go to Kerala and to solve the issue. Back to the present, Karan returns to Chennai with the money to pay the dowry. The day of the wedding, the groom's family ask for more money and the wedding is eventually cancelled. The circumstances force Karan to marry Thulasi on the spot and Vishwanathan died of a heart attack that day. Thereafter, Karan becomes a wealthy businessman while Prarthana is diagnosed with depression and has lost all her memory. To cure his sister, Dileep begs Karan to come to the hospital and a remorseful Karan secretly meets her at the hospital. Later, Prarthana regains memory but the doctor warns them to not disclose about Karan's marriage. When Thulasi comes to know about it, she decides to sacrifice her life and attempts to commit suicide by taking sleeping pills. At the hospital, Thulasi is saved and Prarthana realises that Karan sacrificed their love for the good of a family. Prarthana praises Karan for being a genuine person and she accepts her fate. The film ends with Karan and Thulasi hugging each other.