Poochakkoru Mookkuthi movie tells Revathi (Menaka) who comes to the city from a small town in search of job and to have a good life and as it is with everyone her problem starts with finding a house. Shyam (Shankar) loves to become a popular singer. His parents are dead against his will. So he runs away from home and needs a shelter. Revathi accidentally meets Shyam who too is in search of a house through the common Milkboy, Chikku(Baiju). Chikku offers them both a house if they are ready to pose as husband and wife in front of the house owners.
Supran (Poojapura Ravi), a lender, a miser who doesn't trust his wife Kousalya (Thodupuzha Vasanthi) who is very young to him is their house owner. Revathi in search of job meets Ravunni Menon (Nedumudi Venu) who is a rich man who owns a bungalow in the heart of the city. Ravunni Menon stays with his wife whose name too is Revathi (Sukumari).
Gopalakrishnan (Mohanlal) needs some investment to come up in business and life. But to get started, he has to rob his father (Sankaradi). He is in search of a rich woman he can marry. Accidentally Revathi meets Gopalakrishnan who has come to Ravunni Menon's house to repair the electronic equipment, which he had sold to him. Gopalakrishnan thinks that Revathi is Ravunni Menon's daughter and her beauty enchants him. Revathi comes to know that there is a job in Gopalakrishnan's showroom and manages to get a job with him by cooking up a story.
After office hours, Gopalakrishnan drops Revathi outside Ravunni Menon's house, thinking it to be her house. She always enters the bungalow through the front gate and skips out through the gate itself after hiding in the garden bush. Ravunni Menon's wife sees her coming and going out of the bungalow and starts suspecting her husband. Gopalakrishnan frequently visits the bungalow to visit Revathi, and Ravunni Menon thinks his wife is having an affair with Gopalakrishnan. Further her encounter with 'Thenga' Govindan Pillai (C.I.Paul) makes Revathi believe that her husband has sons and daughters out of wedlock.
Shyam in the meanwhile falls in love with Revathi and to make her jealous, he makes her feel that he has an affair with Kousalya, who in turn thinks to be true and is ready to elope with him after looking her miser husband.