Vallavan movie is about Vallavan (Simbu) who falls in love with Swapna (Nayanthara) at first sight. Later, it becomes known that Swapna is a trainee lecturer in the same college where Vallavan studies and she is three years older.Vallavan turns into Pallan to woo her dream girl. But Swapna spurns his love after learning too late that he is younger than her and decides to marry another man.