| Director | Sri Senthil |
|---|
Seven years ago, a senior lawyer Natarajan addresses a courtroom.
On 22 December 2025, police officer Kaalidas responds to a distress call at an isolated house in Meyyur. On arrival, he is attacked by a group of men, who flee the scene. Inside, Kaalidas discovers a man and a woman murdered by the woman's father.
At S.I.S. Apartment in Urapakkam, a junior lawyer, Stephen, stalks a family. A few days later, Kaalidas is informed about a plot to kill Perambur Murphy by a rival gang. Stephen and Pandya kidnap Murphy, and Stephen kills Murphy. The next day, Kaalidas finds Murphy's dead body.
During a celebration on New Year's Eve, Stephen kidnaps Mithra, the young girl from the family he has been seen stalking. Kaalidas's team arrives at S.I.S. Apartment to investigate. Assistant Commissioner of Police (ACP) Vaishnavi is also assigned to Mithra's case. They find a dead dog, and a resident identifies the owner's residence. The police break in to find a group of friends heavily drugged, but their dog is alive. CCTV footage shows Stephen with the same dog. Stephen is captured as a suspect in Murphy's murder case. It is revealed that seven years ago, Stephen raped and murdered a girl named Dhanya.
Mithra's dead body is found. Senior lawyer Natarajan arrives and releases Stephen due to a lack of evidence against him. Apartment Secretary, Roopa, informs Kaalidas and Vaishnavi that Roopa's daughter had seen Stephen with Mithra. Another girl, Harshitha, drowns in a swimming pool. During his release, Stephen kills one of Murphy's men.
With Natarajan's help, Kaalidas discovers that seven years ago, Mithra's mother was Stephen's girlfriend and a witness in Dhanya's case. Pandya reveals that Murphy's men killed Dhanya and that Stephen is innocent.
Kaalidas meets with Stephen and Stephen explains that he had given his dog to Mithra. With Stephen's help, Kaalidas finds evidence leading to Doctor Prasanna. Before the police can enter S.I.S. Apartment, Prasanna falls to his death. Kaalidas grows suspicious of Roopa, and Roopa explains everything.
It is revealed that one of the heavily drugged men frightened Roopa's daughter, Ananya, and Harshitha. Ananya mistakes Stephen's dog for the drugged man's dog and throws Stephen's dog off the roof. Mithra, who is with the dog, falls to her death while trying to save it. Roopa helps cover up Mithra's death, and Ananya frames Stephen. Ananya kills Harshitha when Harshitha wants to inform the police. Ananya pushes Prasanna off the roof when Prasanna confronts Roopa and Ananya. Stephen visits Roopa's house, and Ananya traps him.
Roopa sets the house on fire and dies, but Kaalidas manages to save Ananya. A trapped Stephen contacts Kaalidas.
Kaalidas understands everything and witnesses Ananya wake up with a smirk.