Oru Modhal Oru Kadhal is a story of a guy (Vivek Rajgopal), who falls in love with a girl, and their trouble-filled journey from Chennai to Bangalore to Delhi giving troubles to his friends and family portrayed hilariously.

The story starts with Vinay (Vinay Rai), who is a mariner and works in ships. One day he visits his native place, somewhere in Kerala, with his son Sam (Jineeth Rath) to meet his father Shankaran (Rajit Kapur). Shankaran is a village doctor or ‘Vaidyan’ and is also a master in astrology and the ancient sciences. Sam is a Diabetic and Vinay wanted to have him treated by his grandfather. Another story line is that of the orphan Meera (Vimala Raman), who has been staying with Shankaran since her childhood, treated as his own daughter and who helps him treat various patients. Vinay and Meera share a special bond and love each other. But when Shankaran studied their horoscopes, he learned that whenever they express their love towards each other, something terrible would happen. Learning this Meera sacrificed her love, and thus Vinay married Sandra (Linda Arsenio) who is a TV journalist. Now after a long time when Vinay returns home with his son, his special bond with Meera develops again with Meera reciprocating the feeling as well. On a parallel track, a corrupt Mayor – Durai (Ashish Vidyarthi)- is fighting an issue of an old dam in his area. Towards the end a leak is discovered inside the dam, and when a heavy storm and rains hit on the same day, a high alert is declared.