Udayon movie revolves around 75 year old Suranadu Kunju and his son Papoyi ( Both are Mohanlal). Kunju thinks that the heartbeat of earth is in soil and not in maths. His beliefs on the land and agrarianism is good but his value system that farmers and farming is more important and better is not. He does not let his sons pursue there interest and wants them to do farming also. Which leads in they becoming negative towards father.Also when he tries to marry off his daughter to an ugly but farming loving another narrow minded character instead of an educated handsome doctor makes them feel that the father is destroying and spoiling their lives with his stubbornness and high handedness. The presence of a villainous brother in law to his sister