Keerthi, an honest police officer, is charged to solve a double murder case. Keerthi faces up to another police officer Naveen Kumar. Naveen Kumar who hungers for a promotion wants to take charge of this affair. Keerthi and Naveen Kumar finally fight, and the matter is taken up in court. Keerthi hires the lawyer Chaturvedi, a senior lawyer who has never lost a case. Later, Chaturvedi has a heart attack and the doctor Mona takes care of him. He really likes the way she took care of him and he now considered her like his own daughter. The doctors Rajasekhar and Mona suspect the hospital running by the doctor Johnson for doing illegal activities. Rajasekhar is later killed by someone, the presumed guilty is Mona according to the fingerprint on the murder weapon. Keerthi and Chaturvedi come to her rescue.
N. Krishnaswamy of The Indian Express said "As the film's script is free from some of the cliches that constantly besiege Tamil films, Naangal is not without its merits as 'time passing' fare".[3]
