What could have been a dream for Arvind doesn't seem like a dream when his lookalike Sivakumar breaks into his house and starts to fight with him. Being a simple, happy go lucky yet unlucky that day, Arvind asks him what he actually wants from him. Sivakumar reveals that he is a movie admirer like him, and wants the entire world to know the greatness of Indian Cinema in the time when it is not regarded as good by its own audiences, who prefer to watch foreign movies instead. Arvind agrees to help him, but suddenly the tables turn on him unexpectedly, which he later turns on Sivakumar, who also turns... As the both keep fighting with each other and spreading humour, O Hero! gives you hardly any idea that who's the real hero here: Arvind or Sivakumar?