Gair Kanooni is an action comedy drama. The Police officer Kapil Khanna wants to catch the mafia don Robert D’Costa (Ranjeet), but has no evidence against him. However, he finds the help of his friend Azam Khan (Rajinikanth), an underworld don with a golden heart. Azam Khan collects the evidence against D’Costa, but before he could hand them over to Police Commissioner Kapil Khanna, he gets killed by D’Costa. Azam’s son Akbar (double role by Rajinikanth) vows vengeance against Kapil, as he considers him responsible for Azam’s death. Will Akbar understand the situation and get the right culprit punished for his sins?