Oru Kaidhiyin Diary

David tries to escape from prison but is caught. As punishment, his sentence is increased multifold, making him endure a harsher term than before.

After 22 long years, David is released from prison and goes to meet his old ally Velappan. He bears the weight of the past and the tragedies that followed. A flashback then reveals the happiness of his family.

A flashback reveals David and Rosy were married and lived a happy life. They have a newborn son named James, and Suryaprakasam blesses the child. This peaceful memory contrasts with the coming turmoil.

David, now politically active, introduces Rosy and James to the party leader Suryaprakasam, who he trusts. Suryaprakasam appears benevolent and supportive in public. A dangerous seed of manipulation is planted.

Suryaprakasam organises a protest that blocks rail traffic, naming David as the leader to ensure his arrest. The plan hinges on David's public image and his commitment to the cause. It sets the trap for the devastating events to come.

David is arrested during the protest, and Rosy comes to him seeking release. Suryaprakasam manipulates Rosy into handing over their baby James to his henchman Arumugam, setting a trap for Rosy as well. The stage is set for a brutal betrayal.

Rosy is forced to submit to Suryaprakasam after Arumugam threatens James. Suryaprakasam rapes her with the help of his henchmen, shaming her and breaking their family. The assault marks the collapse of Rosy's world. The trauma drives her to a breaking point.

Overwhelmed by humiliation, Rosy hangs herself and leaves a handwritten note detailing the crime. The note explains what happened and names those responsible. It becomes a focal point in the unfolding conspiracy.

Velappan bails David out, and the two reunite briefly as David returns to life outside. He walks into a home filled with quiet sadness, knowing what happened to Rosy. The past begins to catch up with him in new, dangerous ways.

David reads Rosy's note and confronts Suryaprakasam at his birthday function. The trio—Viswanathan, Dr. Unnikrishnan, and Suryaprakasam—manipulate the note away from David and burn it, destroying the evidence. David is framed for Rosy's murder, and the courtroom seals his conviction.

The trio lies in court and frames David for Rosy's murder, leading to a conviction. David vows revenge and leaves his only son James with Velappan to be raised, while planning to clear his name someday.

From jail, David learns that Velappan has changed his ways and raised James into a righteous, respected police inspector named Shankar. The knowledge steels David's resolve for vengeance against the conspirators.

After his release, David visits his old church and confesses to the priest that he plans to kill three people. The priest informs the police, who publicize the news and begin pursuing the would-be killer.

David disguises himself as a priest to enter Police Headquarters, demanding to speak with SP Viswanathan. He triggers a hanging trap that kills Viswanathan, witnessed by Dr. Unnikrishnan, who realizes the manipulation too late.

David escapes again and kills Dr. Unnikrishnan with a rifle, aided by Sharadha who sympathizes with his cause. He hides in Sharadha's basement while the DIG's house becomes a focal point of protection for Suryaprakasam. In the climax, David kills Suryaprakasam, and Shankar is forced to shoot his father. David dies alongside Suryaprakasam.