Dosth is all about two friends Shyam (Kartik) and Siva (Siva Balaji) who were happy-go-lucky youngsters who see the world as their oyster. The two college-goers are the most popular in their campus. They are up to every trick in the book. But unbeknown to anyone, the two work in the night so that they can be happy in the morning. In the college, they carry out their fun and games on a newcomer Aparna (Neha). Aparna, however, happens to know the new principal Snehalatha (Suhasini) very well. And when she broaches the issue with the principal, the latter calls over the impish duo and punishes them. But she also realizes there is a true side to them, and hence meets their guardian (Vishwanath). The meeting ends up as an eye-opener for her. It throws up a major secret of her own life. What is that, and what happens after that form the rest of the story.