The story is about Black, a fisherman who is loved by all in his village even though a mentally ill person. He is also the security of Tharakan Muthalali, a famous marine food exporter and is taken care of by his daughter Blessy, who values the friendship of Black a lot. Caesar and George Washington are his two supportive friends who were also Tharakan's securities. Varkechan, Tharakan's brother is not at all happy with Black's eating styles and rebuked him once for eating in his house. Black still continues his childish behaviour and is called by Caesar to accompany Pathrose Moopen to have more food. Later Tharakan receives a call from Prabhul Kumar from Mumbai regarding the arrival of his daughter Meenakshi to Tharakan's village. When Meenakshi was happily shooting the video of festivals as a tribute to her, she gets shocked on seeing Black, a person who exactly looked like Ramesh Sharma IPS, her lover whom she thought had died in an accident. Still suspicious, she decides to find more about Black and finally confirms that Black is Ramesh. Meenakshi after staying for a few days in Tharakan's house moves to house of Moosath, a powerful sorcerer and decided to bring Black back to Ramesh. Black was first impressed by Meenakshi due to her scent of perfume. Tharakan drops Black to Moosath's house for Pooja without knowing Meenakshi's plans. Even though Black first resisted, he patiently gets ready for the Pooja and within days changed to different personality. Meenakshi who was eagerly waiting for seeing her Ramesh, gets an unexpected result from Moosath that the person is not Ramesh and said that he is Black. But Meenakshi firmly believed that he is Ramesh. It comes true when he finally reminisces his fight between Prabhul Kumar, DGP Aggarwal and Prabhul's brother. When he reached Tharakan's house, all got shocked of his different behaviour. He has completely changed his mind. However Tharakan decides to find truth behind Black's change in his behavior. Confused of the languages used by villagers he finally sees a video shown by Blessy and gets an idea of it. When Pathrose bought him food he resisted which even more shocked Pathrose. Black, as Ramesh moves to Mumbai after a gap of ten years to find his enemies and kill them. To get more information about his family, Ramesh goes to his friend Dinesh where he finds that her mother and one sister had already died. His another sister Shyama is taken care by Dinesh and his wife. On his way he reminisces about an incident where he fights Prabhul and team to save his sisters but gets beaten up by them on his head and lost his sanity. After killing Prabhul's brother and DGP Aggarwal, he returns back to Tharakan's village in Kerala and gets arrested by Vikram Dharma IPS who was sent by Prabhul Kumar from Mumbai. The next day he is taken to court and Ramesh brilliantly acts as Black in front of the Judge and his rival lawyer. The lawyer said that the person is Ramesh Dharma rather than Black. Dinesh then brilliantly acts with the proofs regarding death of Ramesh Dharma and further proved that he is Black. When the rival lawyer still did not give up, the judge postponed the verdict for a day. The next day Moosath and Meenakshi too comes to the court and informs that the person is Black and not Ramesh. Dinesh then made the judge strongly believe that the person standing at the court is Black and is left freely. Ramesh then informs Dinesh about his plan to kill Prabhul Kumar who ruined his life. Meenakshi begged Ramesh not to kill Prabhul as he is her father. But Ramesh was firm on his wise decision. But he gets beaten up by some goons on his head again but Tharakan managed to save him. Enraged Tharakan and relatives goes to Prabhul Kumar's house to seek revenge for trying to kill Black. On seeing him Meenakshi gets shocked as Moosath earlier informed her that if he again gets beaten on his head, he could never be brought back as Ramesh. To test whether he is Black or Ramesh, Prabhul Kumar slaps Shyama and Blessy badly. As he did not react in both the cases, Prabhul confirmed that he is a mad person and tells Tharaksn to take him back. Tharakan angrily threatens Prabhul and takes back away. However when Prabhul came to know that Meenakshi knew his role on hitting Ramesh, he orders Vikram to kill Ramesh. As Prabhul was about to shoot Ramesh, he gets blocked by Ramesh and gets killed after a wrestle with him. However court leaves him free handed. Everyone is still upset as they thought that Ramesh again got lost his regained memory. But Ramesh reveals the truth behind his act. Ramesh also comes to know that Blessy got to know his real identity and story. Then film ends as Ramesh completely changes back to Black Cat and greeted by Tharakan and relatives.