Midhunam movie is all about Sethumadhavan (Mohanlal) who has plans to start a biscuit factory near his house. But the bureaucracy and the corruption of the officials are the hurdles in front of him. Along with that he has to solve the problems in his family, which his brother (Innocent) and brother-in-law (Jagathy Sreekumar) creates. he marries his long-term fiancée Sulochana (Urvashi) who always cribs that he doesn't have love towards her, which he had shown before their marriage. How sethumadhavan succeeds in his life beating all the odds against him forms the rest of the story.

Vijayan, the village school teacher, believes that his degree in economics is sufficient for him to succeed in the business ventures he undertakes. Taking long leaves of absence from work, he roams around with his schemes, all of which turn out to be downright failures.

After his retirement, Raghavan Nair (Thilakan) is back at his home. His long cherished dream to spend his retired life along with his family is thwarted after seeing his two sons brawling each other over their political differences.

A young woman is dumped by her boyfriend just before the wedding as she will not be inheriting any wealth from her father. When the girl's father pays her a visit, she hires a man to act like her husband.

A man with a serious case of inferiority complex is married to a beautiful girl. Soon, his love and care turns into suspicion.