9 months after having killed extortionist Mayil Vaaganam (Prakash Raj) in Singam (the first film), Durai Singam (Suriya) has gone undercover after meeting Home Minister Ramanathan (Vijayakumar) and is now working as an NCC master in a Thoothukudi school. The people who know about this operation are the Chief Minister (K. Viswanath) and Ramanathan. Sathya (Hansika Motwani) is a student who falls for Singam, though he is waiting to marry his love interest Kavya (Anushka Shetty). Singam's father Soundara Pandi (Radha Ravi) is angry about him leaving the police force. He also forbids the marriage between Singam and Kavya, as he fears that Kavya's father Mahalingam (Nassar) might take Singam away to manage his business empire and that Singam will lose respect within his relatives.