Passenger is based on two characters, who never had anything to do with each another, who come into each other's lives. The movie shows the events that follow. Sathyanath (Sreenivasan), who works in a private company, is a simple man who lives an orderly and uncomplicated life. He travels from his native town to Kochi (where he works) by train. The moment the train crosses the Chalakudy bridge he dozes off. And he wakes up at a particular point. All this happens with utmost precision as if programmed by someone. He is someone who fights for social justices for the benefit of everyone and shirks from any publicity gained by it. Nandan Menon (Dileep), who is an advocate, stands for truth and justice. He respects the law and always thinks of the welfare of the people around him. His wife Anuradha (Mamta Mohandas) is a bold reporter who works for private news channel Right TV. Maranchara is a small fictitious coastal village. A private company has been awarded rights to mine nuclear fuel from the coast in Maranchar by Home Minister Thomas Chacko (Jagathy Sreekumar). There are a political sex scandal and a legal battle within which Minister Chacko, Nandan Menon, Anuradha Nandan and Thankamma (a local leader) are involved. The plot takes a turn when Anuradha obtains a video clip of the minister collaborating with police and corporates. They plan to kill innocent people occupying land with potential mineral resources. Nandan is kidnapped by gangsters working for the minister to lure Anuradha into returning the video. By sheer coincidence, Sathyanath gets involved. Unlike normal bystanders, he and Driver Nair (Nedumudi Venu) decide to join the couple in the fight to save the people of Maranchara, Nandan Menon, and Anuradha.