Umman, Balu and Addu, the childhood buddies are nonetheless collectively, working in the identical firm. Recognized for being the unhealthy apple and the quitters of Minerva Bio-Chemical compounds, the trio has one other buddy within the workplace, named Unnikrishnan Namboothiri, who's essentially the most courteous individual in addition to one of the best worker of the workplace. Rony who was well-known for his mischief and who had studied with the trio as soon as throughout their college time is once more coming to their workplace as their new colleague. The issues in Mariam Vannu Vilakkoothi begins when the chums determined to have a good time Namboothiri's birthday on the place the place he stays as a paying visitor, on the home of the Retired Head Mistress Mariamma George who's an austere and stern girl.