Pasupathy is a film that deals primarily with mother-son sentiment.

Pasupathy (Ranjith) is very affectionate towards his mother (Rani). He spends all his time serving her and carrying out all her errands. He is so attached to her. he even stops attending school to be always at his mother's side.

Pasupathy travels to Chennai in search of greener pastures. As soon as he gets down at the bus stop, he is robbed of all his belongings. Deprived of all essential things for living, including his job prospects, Pasupathy spends a restless day there, unsure of what to do.

The police nab him, suspecting him being an antisocial element or terrorist, and forcibly take him to the police station. The Inspector of Police, Das (Vivek), listens to his tale and Pasupathy becomes a close ally, carrying out odd jobs at the station.

He gets acquainted to Priya (Sindhu Tholani) and both of them become good friends. Suddenly, Pasupathy's mother falls sick. He rushes to her side and is informed she needs a heart surgery for which he has to collect Rs. five lakhs at short notice.

A terrorist gang lead by Ilavarasan promises Pasupathy the sum on the condition that he agrees to carry out an unlawful assignment. Pasupathy agrees, but when he attempts the task, he gets caught. The gang appeals for his release.

Meanwhile, the surgery on Pasupathy's mother goes well. But she does not regain consciousness. Pasupathy is shocked to find her in such a state and assuming that she is dead, collapses on her.

Vivek's comedy and his role are the highlights of the movie.

Ranjith has taken up a sentiment-oriented story, which is different and new to Tamil cinema.

Deva has scored music; direction is by Selabharathy.