Mafia: Chapter 1, known simply as Mafia, is a 2020 Indian Tamil-language action crime film directed and Written by Karthick Naren and produced by Allirajah Subaskaran under the banner of Lyca Productions. The film starring Arun Vijay and Priya Bhavani Shankar in leading roles with Prasanna playing the antagonist.
The movie starts off with a hotel, where a gunshot was heard and immediately the police arrived. It stops there and immediately shifts to the main lead, Aryan (Arun Vijay). Aryan is a Narcotics Control Bureau Officer who works alongside his batchmates Sathya (Priya Bhavani Shankar) and Varun (Bala Haasan). Aryan lost his twin Brother, Dillip (Arun Vijay), to drugs, therefore he becomes a Narcotics Officer and his main aim is to eradicate all drug groups and drug lords, known as the ‘Snake’s Den’. Alongside his team are Selvam, his team supervisor and Mugilan (Thalaivasal Vijay), a social activist who is also Aryan's neighbour. Whilst Aryan arrives home after catching two culprits that were into drugs, he receives news that Selvam (Aroul D. Shankar) has died due to a gunshot at the head. Previously, Selvam had concluded the guy behind this, but did not reveal so the culprit wouldn't know about this. Aryan and Sathya investigate around the house, and Aryan concludes that there is a big drug lord behind the murder, and they must find evidence of that.
Mugilan is also targeted by the drug lord and his bodyguard and is killed. Before his death, he puts information about the drug lord in a USB stick, attached to his dog, Pogo's collar and sends Aryan a message. Aryan tracks Pogo down with the tracking chip installed in his collar and sees the information. The drug lord is apparently Diwakar Kumaran (DK) (Prasanna), a big philanthropic drug trafficker. Mugilan suspects his early source of income was with links of international drug cartels. DK and his brother/bodyguard Rudra (Inder Kumar) have links with politicians, so their business cannot be derailed. Knowing this Mugilan and Selvam decides to investigate a place thought to be Diwakar's secret hideout. Through this they were both caught.
Aryan later moved on to start a shootout at the place, and finally concludes Diwakar's role in drug dealing. DK, knowing what will happen, abducts Aryan's family and asks Aryan to meet his doom at a warehouse. With a plan, Aryan and his team, tries foiling all of DK's plan in one night. After an interesting cat-and-mouse chase, Aryan finally manages to catch DK, who kills himself to prevent going into custody. This is where the start of the movie comes in. Before his death, DK tells Aryan that he is not the main drug lord. Then later it is followed by a twist that his own twin brother Dilip aka Dexter (Arun Vijay) is the main drug Lord, who swears revenge on Aryan, since Diwakar and Dilip escaped a police Attack and found a bounty to start their drug businesses and Dilip was thought to be dead. The story then leads to Mafia: Chapter 2.