Hum Dil De Chuke Sanam story of the movie is adopted from Maitreyi Devi's bengali novel Na Hanyate. Indian-based traditional family of Pundit Darbar (Vikram Gokhale) gets a visit from Sameer Rafilini (Salman Khan), from Italy, who has come as a pupil to learn music and singing. Darbar and his family accept him.
Sameer meets Nandini (Aishwarya Rai), Darbar's daughter, and both fall in love. But Darbar wants Nandini to wed Vanraj (Ajay Devgan), and has Sameer swear that he will leave India, and not marry Nandini, as his guru-dakshina (fee), to which Sameer agrees. Nandini is heart broken, but does reluctantly marry Vanraj.
When Vanraj finds out that Nandini is in love with Sameer, he takes her to Italy, so that both can be together again. Nandini must now come to terms with living with Sameer in Italy, or alienating her family and her new groom.