Madambi tells the story of Puthenveettil Gopalakrishna Pillai, a man of many faces. The story begins 25 years back when Gopalakrishnan's father, who was a man with artistic temperaments sells off everything and goes away. Young Gopalakrishnan goes in search of his father and comes back to find that his mother and younger brother Ramakrishnan, seeing no future, are on the brink of suicide. From then on he takes charge.
Everything, including their ancestral home, had been lost and it's just an elephant that remains. Gopalakrishnan begins with that and gradually picks up in life. In the course of years, he becomes a financier who gives loans to people at low interest rates; but he is rather demanding when it comes to taking back the capital or collecting the interest. He also runs a tuition centre, which is managed by his younger sibling with able help from Divakaran Nair and Kumaran, both of whom had always been their well-wishers.
In the meantime Parameswaran Nair, (who had long ago cheated Gopalakrishnan's father), and his two sons Sreedharan and Reghu continue to make moves against Gopalakrishnan. Things take a new turn when Ramakrishnan falls in love with Shyamala, who is Parameswaran Nair's daughter. Though Sreedharan and Reghu oppose this, Parameswaran Nair supports and encourages this love. He has his own motives in doing so. As the plot develops we find Gopalakrishna Pillai pitted against his mother (who had always been against him) and his brother Ramakrishnan in a legal battle for the property. There is also Jayalakshmi, the manager of a newly opened bank, who is kind of a competitor to Gopalakrishna Pillai in his financing business. All these lead to the climax of Madambi.