Mazhayathu tells the tales of a Malayali middle-class family consisting of Venugopal, a simple man and an overprotective father, Anitha, an ambitious wife and Ummi, the daughter who depends on her father for everything. Although the couple has their usual tiffs and banters, they live a happy life. One day, a bizarre incident shakes the whole family and ruins their happiness. Venugopal finds himself being the victim of people's angry reactions and to make matters worse, he is shocked to find the reason behind the reactions. What exactly happened? Will Venugopal redeem himself?