Arya, Hansika Motwani
The story begins in Goa where six dead bodies are washed ashore. The Goa Drug Lord, Jothi(Ashutosh Rana) is responsible for this. The Police Department of India are unable to capture him for nearly a decade, because not a single person has seen him in person and he is constantly on the move and also has no permanent aides or accomplices.
Chitti (Mahadevan) is in charge for the drug trafficking in and around Goa. One day, he receives a call from Jothi about a missing drug consignment. Chitti and his men are unable to hunt down the culprit. It is revealed that Shiva (Arya),is the mastermind behind the drug theft. We see that Shiva is working for Chitti as his most trusted henchman. Chitti, along with Shiva and his nephew Guru (Harish Uthaman) run an underworld drug empire in Goa.
In a turn of events, we see that Shiva is actually Arul, an undercover police officer who is assigned to expose Jothi and his entire drug cartel. He receives instructions from his higher officers Bharathi(Anupama Kumar) and Benjamin Vas(O.A.K.Sundar) and he also informs them about all the activities of his gang from time to time. Arul is into this mission along with his best friend and colleague Karthik (Ramana) who also takes a stage name as Maanik, and he works for Sharma (Ashish Vidyarthi), another drug lord from Mumbai, who is in possession of 1000 kg of pure heroin and is presently, looking for a buyer.
The plan of Bharathi, Benjamin and their team is to make Sharma and Jothi meet each other for the transaction of the 1000 kg of heroin and then arrest them together. Arul informs Bharathi that initially Sharma and Jothi are planning for a trial with just 100 kg of heroin and that, if all goes well, they will deal with the remaining 900 kg. Bharathi and her team wisely plan to capture the huge bulk of 900 kg of drugs along with Sharma and Jothi. So they have to leave the first trial transaction unmonitored. However, all plans go awry when Bharathi's jealous boss does not agree to her plan and conducts a raid for the trial transaction in the last moment. This exposes the cop Karthik and he is taken to Chitti's place and tortured by Guru and his gang to reveal the identity of any other man working with him.
Unable to bear the pain, Karthik reveals that Arul is the other undercover officer. Guru informs Chitti about Arul's true identity and when they attempt to kill him, Arul guns down Chitti and starts eliminating all the gang members including Guru. Soon, Arul finds Karthik but within moments, Karthik dies.
Jothi is now aware of the death of Chitti and his entire crew and uses his influence to the police officers to bring Arul into his custody. So, the police force and Jothi's men join hands and hunt for Arul. Arul, now all alone on this mission, still continues his own plan to expose Jothi and gets himself captured on purpose. Now that he has nothing to lose, he plans to play a final game of chance to meet Jothi face to face and earn his trust and join as henchman again. Arul is the only survivor of the shootout at Chitti's place and so only his account to Jothi will earn his trust.
Arul is brought to Jothi for the first time and he is also able to cleverly convince him, but only up to an extent. He tells Jothi that his former partner-turned-archenemy Rane (Sudhanshu Pandey) is responsible for the drug theft(mentioned at the beginning),and shootout at Chitti's place. He says that all this while Jothi had been thinking that Rane was dead, but now he is actually alive is plotting his revenge. Jothi is still skeptical, so Arul is given 48 hours time to prove that Rane is alive and has done all these things. Arul succeeds by getting help from a prostitute (Sanjana Singh) whom he helped earlier. He also places all the stolen drugs at Rane's house and leads Jothi's men there, and they find the lost drugs. Jothi asks his men to kill Rane and his gang. Shiva cleverly does certain manipulations and kills Rane and his men and places his own guns in Rane's hands. This leads Jothi and his men to believe that Rane's gun and the one used in the shootout at Chitti's place are one and the same.The gun is also sent the gun for ballistic testing to check on Shiva's story and they all believe that Shiva's story is true.
Soon, Jothi asks Arul to join his gang and meet him at a secluded place. When Arul waits for the opportunity to gun down Jothi, he gets beaten up by his men. It is then revealed that Usha (Hansika Motwani) , his neighbor who has a huge crush on him , had been secretly recording videos of him on her phone, for her to admire. But her phone is stolen and it falls into the hands of Jothi's men. They find whom Arul has been meeting and dealing with so far and they come to know that he is also an undercover cop. As a result, Arul's bosses Bharathi and Benjamin are assassinated by Jothi's men. Jothi and his men then beat Arul savagely and keep him bound in a harbor and ask him the whereabouts of Sharma's remaining 900 kg of heroin. Arul whispers the location and as Jothi comes closer to hear him, Arul spits out a blade at Jothi's eye. When all his men are distracted momentarily, Arul escapes from his captors and kills them leaving Jothi alone and arrests him. Since nobody alive has seen Jothi in person, his arrest is unavoidable and no political influence will work out anymore.
As the credits roll, we see that Arul humbly rejects Usha's proposal and asks her to focus on her life. Arul then moves on to his next mission and kills Sharma and seizes the remaining 900 kg of heroin.