Three girls, Yamini, Tulasi Mani and Radhika, are found killed in a train journey in mysterious circumstances. Sharafudeen Rahman (RK), from RACT (Railway Anti Criminal Task force), takes up the case and starts the investigation by enquiring all the passengers and employees in the train who travelled on the day the assassinations took place. He is assisted by characters played by Nasser and Ramesh Khanna. As the investigation progresses, Rahman and his team get suspicious about Kumara Swamy (Siddique) and Karikalan (Suman) owing to their behaviour. The murderers of Tulasi Mani and Yamini are found by RACT without much effort, but Radhika?s assassination leaves the team puzzled. How they find the culprit after a series of thorough investigation forms the rest of the story.