Chandrasekhar (Mohanlal) is an IPS officer who lives a lonely and quiet life after being divorced from his wife, Deepthi (Priyamani), a leading criminal lawyer. Things change when he is made the head of the Metro Crime Stopper Cell in Kochi, and single-handedly saves three college girls abducted by a psychologically deviant guy. Chandrasekhar gets a congratulatory note from an anonymous man calling himself “Z,” who challenges Chandrasekhar to figure out how he is going to bump off one target after the other. Chandrasekhar is forced to take up the investigation of the murders, which follows a mysterious alphabetical pattern.
A veteran cop chases a cold blooded serial killer, who murders his victims in alphabetical order.