The story of Seethakaathi surrounds around a character named Ayya Aadhimoola (Vijay Sethupathi), who is passionate about theatres and drama. Ayya, who earlier refused doing moives all his life, starts acting in them and becomes superstar. Ayya disappears leaving his friend Parasuraman (Mouli) and family to face Dhanapal (Sunil) a wealthy producer and actor, who was suppose to produce a movie with Ayya. What happens to Ayya? Is explained in rest of the story.