The entire film happens in a day. Ramalingam Pillai (Major Sundarrajan) working as Head Clerk at Sun Beam Exports and Imports is about to leave to office. His wife Meenakshi (P.K. Saraswathy) is concerned about the grocery dues when the milkman comes home and starts shouting. On seeing Ramalingam, he lowers his voice. Such is the respect Ramalingam commands due to his personal integrity and value system.
Ramalingam's daughter Kamala (Vasantha) and son-in-law Raghupathi (Chandiran) live in the same city. Raghupathi working as a cashier at Sudarsanam Bank is worried because he had mistakenly given excess cash to a customer and the bank has told him to pay the amount by 4 p.m that evening, failing which the Police will be informed. Kamala decides to get help from her father.
On way to Office, Ramalingam is stopped by the temple priest who informs him that Ramalingam is appointed as the chairperson of the fund donation drive for the temple renovation and that his chairmanship will increase credibility. Ramalingam resists, but the priest convinces him. Kamala stops him to talk about Raghupathi's problem at that time. But he says he is already late for office and rushes to catch the bus.
Ramalingam is the first person to enter the office followed by the two peons Simon (Nagesh) and Kannayi ram (A. Karunanidhi). Ramalingam tells Simon to inform him when the owner arrives as he has to submit his son Ramu's job application form.
The other clerks like Paramanandam (V.K. Ramasamy) and many others arrive later and none of them work sincerely. The new Manager Shekar arrives, who is educated abroad and the owner Raja's (Srikanth) friend. He is unable to accept Raja's dependence on Ramalingam and becomes hostile towards Ramalingam. Finally, Raja arrives and meets Ramalingam and gets an update on the business and requests his guidance.
When all his efforts fail, Raghupathi meets Ramalingam and asks for help to pay his bank. Ramalingam is shocked to hear the sudden requirement of money and assures to try his best.
Ramalingam thinks of taking a loan from the owner but realizes that Gurusamy, one of the employees has already asked for a marriage loan and plans to ask if Guruswamy doesn't. However, Gurusamy takes the loan and hands over the money to Ramalingam to keep it safe until the marriage. For a moment, Ramalingam thinks that he can temporarily use that money but then stops the thought as ft is against the trust Guruswamy has in him. One of the employee's says it was foolish of Gurusamy to have given the money to Ramalingam without a receipt and Gurusamy retorts that Ramalingam is like God and can never cheat anyone. Simon shares this with Ramalingam and he feels a heightened sense of responsibility to keep the money safe.
The company is looking for a new vendor and there are two competing for it. The previous day one of the vendors offers a bribe to Ramalingam and he throws him out. Now Ramalingam thinks of calling that vendor and tells Simon to inform him to meet him at a specified time. But his conscience pricks soon and he decides not to take the bribe and calls off the meeting. The occurrence of the very thought of taking bribe upsets Ramalingam and he informs his son Ramu about his inability to organize the money.
Ramalingam waits to meet Raja, to get the job for his son. But then, Kannayiram approaches him requesting him to get a job for his son. Ramalingam, who always helps the needy, the gets-the job for Kannayiram's son.
It is 4 p.m and Ramalingam is worried about his son-in-law. Raghupathi arrives there and tells him that the same customer had returned the excess money he received. Raghupathi apologizes for the unnecessary trouble and a relieved Ramalingam gets back to work.
Ramalingam completes all his work and writes his resignation letter as he feels that he was almost about to compromise in his job by deciding to take the bribe. He meets Raja and hands over his resignation. Raja is shocked and refuses to accept it However Ramalingam requests him to accept it as a token of gratitude for working for 35 years in that company. Raja accepts it and everyone at the office is shocked. While stepping out of his office room, Ramalingam requests all the other employees to be sincere at work. They feel sad about losing such a genuine person like Ramalingam. He takes permission from Shekar to sit in his chair one last time. He asks for water from Kannayiram, drinks it, and dies in the chair itself.
The portrait of Mahatma Gandhi with the slogan 'Truth alone triumphs' is replaced with Ramalingam's portrait. Raja calls for a meeting of all employees and also Ramalingam's family. As a token of gratitude, he offers a part of the company shares to Ramalingam's family and also gives the head clerk job to Ramu.
[from the book Pride of Tamil Cinema: 1931 to 2013 by G Dhananjayan, Blue Ocean Publishers, 2014]