Philip Manavaalan is the owner of a Kerala-based financing company, and the film opens with his wedding preparations. After the ceremony, his wife Cecily grows curious about his dead brother, Raju, and Philip begins to tell Cecily the story of what happened.
Raju is depicted as a bright, capable young man with many talents, but he is easily drawn into drug use. He starts siphoning money from his brother to fuel his addiction, a pattern that forces Philip to admit him to a rehab facility. Raju seems to turn the corner and is sent to Madras for further studies. Yet during a visit to Chennai, Philip realizes that Raju has fallen back into old habits, perhaps even worse than before. One night, Raju steals some money and runs off with Philip’s car, and soon afterward a call comes reporting that the car has crashed and the driver died in the explosion. Philip performs the last rites in Chennai and returns to Kerala, while Cecily offers quiet sympathy.
Nevertheless, Raju unexpectedly returns home, leaving Philip shaken and suspicious. To determine if this is truly his brother, Philip subjects the visitor to a series of tests with the help of his friends, and each test yields a convincing result that seems to prove Raju’s identity. The circle of witnesses grows: Renu, the daughter of Philip’s police-officer friend Cherian, has become convinced that Raju has come back and begins an affair with him. Cherian and their common friend John attempt to persuade Renu to abandon the relationship, but she remains certain that Raju has returned and declares she will marry him.
Seeking a final, objective verdict, Cherian decides to conduct a more scientific check. He travels to Chennai, where Raju’s body was cremated, and digs up the remains. He photographs the skull and compares it with Raju’s face, only to discover a mismatch. He informs Philip, who visits Cherian with a growing sense of doubt, yet still cannot accept the possibility that the man at his door might be an impostor.
Philip ultimately reveals the truth he has kept buried for years: on the night Raju died, the younger man tried to steal money from Philip’s cupboard and leave his brother’s shadow behind. When Raju refused to listen, a confrontation ensued on the stairs, and Raju fell from the first floor, breaking his neck. Philip rushed to help but knew the tragedy could be charged as murder, so he disposed of the body and drove it to Chennai, where it was pushed off a cliff and exploded upon impact. He returned to Kerala with a heavy secret.
Cherian then discloses that he had already suspected the real fate of Raju, thanks to a Chennai police officer named Akbar who was investigating the case. To prove that Philip was the true killer, Cherian and Akbar hire Albert, a lookalike of Raju, to impersonate the brother. Realizing he has been duped, Philip decides to surrender. Before Akbar takes him to Chennai, Philip asks Albert to look after Cecily and to marry Renu, entrusting their futures to others who might still find happiness.
