The story revolves around a train journey in No. 20 Madras Mail. Tony Kurushingal along with his friends Hitchcock Kanjikuzhyi and Kumbalam Hari see Mammootty along the way. Having had a few drinks and intoxicated, Tony and friends are in a playful mood and are having fun. Tony attempts to flirt with a girl in the next compartment, Devi, leading to Tony landing in trouble with Devi’s father, R. K. Nair, which Mammootty helps resolve. In the morning, as the train reaches Madras, Devi is found murdered in the toilet. Suspicion lands on Tony and friends. Hunted by the police and Devi’s boyfriend, they seek Mammootty’s help as he is the only person who does not believe they are capable of being behind the murder. The plot follows their attempts to escape and find out who really killed the girl.