The film starts on a fresh note, with Aadhitya, a software engineer, and Nithya, a marketing executive, connecting through a dating app. As they spend more time together, they begin to develop feelings for each other. However, their relationship is put to the test when they face various obstacles, including disapproval from their families and misunderstandings.

"O Kadhal Kanmani" is a Tamil romantic comedy-drama film written and directed by Jithu Joseph. The movie stars Nivin Pauly as the male lead, and Amyra Dastur as the female lead. The film's plot revolves around the life of a young woman named Naina (played by Amyra Dastur), who falls in love with a man named Karthik (played by Nivin Pauly). The movie explores their relationship, highlighting the highs and lows of love, trust, and relationships.