Action Jackson is an action romantic drama that revolves around Vishi (Ajay Devgan), a small-time crook who would do anything for money. Vishi falls in love with a simple rather clumsy girl, Khushi (Sonakshi Sinha), who is an HR executive. The two start dating and go on to embark on their romantic journey. However, their lives take a turn when Vishi comes face to face with his look-alike A.J., a professional assassin working for an underworld criminal Xavier Fonseca. A.J. parts ways with Xavier who vows to finish the former for knowing all his secrets but Vishi and A.J. join hands to get each other out of the mess.