Former Police Commissioner Shanmuga Sundaram, is murdered by a released prisoner named Kamal Ekambaram. The story then shifts to Masilamani a.k.a. Masss and his friend Jettu who are small-time con artists. Masss meets Manini, a nurse, and they subsequently fall in love. While trying to escape after a heist gone wrong, Masss and Jettu met with a car accident, post which Masss starts seeing dead people, with whom he can communicate. Jettu dies in the accident and is now a ghost, too. Masss forms a group of loitering ghosts to earn money by performing fake exorcisms and extorting money from scared, rich people, while promising the ghosts that he would fulfill their last wishes in return. Meanwhile, Manini, who thought Masss was working in a finance company, gets to know about the fake exorcisms and leaves him in his plots.

One day, Masss meets a ghost called Shakthivel (Shakthi), a Sri Lankan Tamil and lookalike of Masss. Shakthi initially seems to help Masss to pull off a large heist. However, he wants to use Masss for his own needs. He sabotages the plan and tricks Masss into running over Anthony Xavier, a hawala broker. Corrupt ACP Vikram Lakshman takes charge to investigate the case and learns that Masss is somehow involved in the murder. Meanwhile, the ghosts start striking against Masss as they assume that he is just making use of them and would cheat later on. Masss yells at them and orders them to leave. Just then, Shakthi arrives upon the request of the ghosts. They leave with Shakthi, while Jettu manages to convince Masss. Masss agrees and fulfills the wishes of the ghosts where they attain salvation, which makes him a better person. All these good deeds of Masss, change Manini's assumptions on him positively.

Meanwhile, Shakthi manages to use Masss to kill another person, Madhivadhanan (Madhi), an Member of Legislative Assembly (MLA) and associate of Anthony. While Masss is furious with Shakthi for having made him a double murderer, Kamal meets Masss and starts telling him about Shakthi's past whereby Masss learns that he is in fact Shakthi's son. Shakthi was a cop in Quebec City, Canada, who married Anuradha (Anu), a teacher in his daughter Megha's school, just for Megha's wish. Shakthi secretly learned that Anu really loves and takes care of Megha. Soon, they both fell in love, and Anu gave birth to a son (Masss). Anu owns an acre of land in India, which she wanted to donate to an orphanage, where a new orphanage could be built there. Kamal, who was the only family-friend of Anu in India agreed to help with the registration. Shakthi and Anu, along with Megha and infant Masss, arrived at India to complete the registration, but learn that Industrialists Radha Krishnan aka R. K, along with Anthony forged documents and planned to take the land away to construct flats. Since Shakthi remained undeterred and did not give way, R. K., Anthony, Madhi and Sundaram, along with their henchman killed Shakthi, Anu, and Megha and pinned the murders on Kamal for which he was imprisoned for all these years. Masss survived because Megha had left him safe in a small house of a poor family nearby.

Through Masss, Shakthi wanted to kill all the people who were responsible for his family's demise. Knowing the truth, Masss decides to kill the last person, R. K, himself. R. K. knowing who Masss is, tries to kill him, but Kamal saves Masss. However, because Masss being hit on the head by R. K., loses the ability to see and converse with the spirits any further. With the help of Vikram, who was bribed by Masss to double-cross R. K. Masss finally kills R. K. As Shakthi's last wish is fulfilled, he obtains salvation and joins Anu and Megha in heaven . Manini reunites with Masss, and they get married, but Jettu remains on earth