Jose, a Circle Inspector of Police, Special Branch from Trissur, Kerala, who comes from a respected and well-known conservative christian family, is on the lookout for a suitable bride who fits within his idea of an ideal woman. When he meets Lynta, he believes he has finally found the right woman and the two get engaged soon. However, he slowly realizes that he his not romantically attracted to her and to make matters worse, he finds himself attracted to Anupama Neelakantan, a social activist whom he meets during the course of investigating an abduction case. As he finds himself torn between his fiance and Anupama, he discovers the life secrets of Anupama. Whom will he marry and will he able to complete the investigation successfully forms the crux.
The film focuses on a very conservative Namboodiri family in a very regressive social milieu. Ishti centres around two main characters, a 70-year-old Ramavikraman Namboodiri, who is a Vedic scholar who preserves the fire from a Somayagam to light his funeral pyre, and Sreedevi, his young, third wife. Sreedevi stands up against orthodoxy. She manages to inspire her husband’s son from another marriage to read and write. The conflict between these characters and those who revolve around their lives is what the film is generally about. It then also becomes a strong comment on the attempt to balance worldly desires and the rigidity of caste and tradition.