C Kalayana Raman comes to a village to do his research work. However, he finds himself entangled in the case of Latha, a woman who died under mysterious circumstances.

Vijay Kumar, a detective, goes undercover to investigate the mysterious murders in Ponvel village. When he dies, Anand, his brother, decides to unravel the mystery behind his death.

When a rich man is murdered on a running train, Inspector Shankar tries to solve the mystery. Since Ravanan is the only passenger travelling with the deceased, he decides to help him.

After an officer is shot dead, a CID officer, Shankar, is tasked with investigating to find his colleague's killers. He soon starts unravelling the mystery behind his colleague's death.

Shankar, a CID officer, is tasked with investigating the mysterious murder of a politician. When he realises the involvement of a terrorist group, he decides to capture them.

Rajan, a radio engineer, is found dead under suspicious circumstances. CID officer Sivanandham unravels the mystery surrounding the murder and the suspects that include Rajan's wife and his brother.