Most of the thrillers being churned out in Kollywood either begin with a young couple setting out on a journey to an isolated place or staying in a mysterious bungalow where things become messy. Though Vasantha Mullai, too, follows a similar template, the idea that it adopts is decent enough to grab the attention of the viewers. But then, mediocre storyline and unrealistic conflicts make this an average watch.
Rudhra (Bobby Simha), an IT professional, suffers from blackout disorder due to lack of sleep. His girlfriend Nita (Kashmira Pardeshi), requests him to take a break from work and go on a trip to a hill station. They stay in a villa called Vasantha Mullai, where things seem to be abnormal.