The film stars Tamannaah Bhatia, Prem, Yogi Babu, Munishkanth, Kaali Venkat, Sathyan and TSK.

Saravanan, an NRI living in Kuala Lumpur, Malaysia, arrives in India after hearing the news of the Wayanad floods.

Vetri conspires with Guru to force Saravanan to sell his house cheaply by fabricating and peddling the ghost story.

Senthil and his friend Tulasi meet Kaali and Raju coincidentally at the hospital, and they all desperately need money.

Senthil has to care for his amnesiac mother and needs cash for cardiac surgery to treat the hole in his heart.

Paaripooranam, who poses himself as an agent of famous cinema producers in Kollywood, dupes Kaali, who is so infatuated with movies that he starts enacting the roles he watches.

Thangam, a drunkard who drinks after the clock ticks 9 p.m., bets on a cricket match in an inebriated state and loses the money he saved for his son's surgery.

However, all four friends remain calm due to their peculiar habits, like Kaali, who starts acting out scenes like Vikram from Anniyan.

Vijay Karupaati refuses to sell the house after he insults Meera and Nivetha, calling them orphans.

Saravanan gets infuriated and kills the entire family by poisoning their food and burning them, excluding his mother.

He appreciating Ghibran's score and Dani Reymond's cinematography but felt Bhatia was underutilised, and concluded that "Petromax is more of a time pass comedy caper than a horror film.

"[6] Thinkal Menon of The Times of India gave the film the same rating, saying, "A plot like this require[s] a few nail-biting moments, but the screenplay fails to engage audience in crucial scenes and becomes too predictable, making it a little difficult for viewers to empathise with the lead characters".