In Harihar Nagar

A man with a briefcase arrives at a hotel and swaps it with a second man in the lobby. Moments later, the third man flees into a waiting car, pursued by two others. The car stops, the driver shoots the fleeing man in the head, takes the briefcase, and walks away.

The narrative jumps to a year later, in Kochi. Four unemployed bachelors—Mahadevan, Govindan, Appukuttan and Thomas Kutty—live in a housing colony called Harihar Nagar. Their bachelor lifestyle centers on chasing women and dodging responsibility.

Maya and her grandparents relocate to Harihar Nagar, making her the attractive new neighbor. The four men spy on her to learn more, staging schemes to impress her. Their attempts backfire, and their mischief draws the grandmother's ire when she catches them peering into her window.

The friends bribe the postman to obtain a letter Maya sent, which reveals she has come to Harihar Nagar to learn about her brother Sethu's death. She suspects Sethu's death was not a suicide but a murder concealed as a tragedy. The four decide to present themselves as Sethu's friends to Maya.

At Andrews' mother's house, Maya asks for any information about her brother. The four men approach, pretending to be Sethu's friends, and manage to obtain a photograph of Sethu by claiming it is for the colony's sports club. Maya, seeing the photo, begins to believe they were connected to Sethu.

Thomas Kutty meets Maya at the boxing club, pretending to be a boxer to impress her. He knocks down the other three men to demonstrate bravado, but the ruse threatens to betray them. The four grow uneasy as Maya's suspicions rise.

The four fabricate a story about Sethu having an affair, using manipulated tears to convince Maya of their sorrow. They claim Sethu's supposed romance explains the tragedy and the involvement of his bike owner's henchmen. Maya fights back her suspicions as the four fake sadness.

Honai, a determined antagonist, kidnaps the four men under the pretext that they must be released in ten minutes. He intends to retrieve the briefcase that Maya believes is connected to Sethu's life. The friends fear the worst as they are pulled into a dangerous web.

Maya learns from Annie Philip (the nun Sister Josephine) about Sethu's past and his connection to Andrews. Annie explains how Andrews' father was murdered and how money tied to the briefcase funded a business empire. The revelations complicate Maya's understanding of Sethu's past and deepen the web of motives behind the thefts and lies.

Back in Bombay, Sethu gives Honai a briefcase identical to the one Annie once had; when Honai opens it, it is filled with bricks instead of money. Enraged by this trick, Honai kills Sethu in a violent confrontation. The murder heightens the feud and misleads the four friends about who is truly to blame.

With the brick-filled ruse exposed, the four manage to escape but are relentlessly chased by Honai and his associates. Maya and her grandparents, misled by earlier miscommunications, call the police in a bid to salvage the situation. The pursuit snakes through the city as the truth remains buried beneath conspiracies.

Maya and her grandparents are kidnapped by Honai, heightening the danger for the four friends. They stage a daring rescue, fighting through Honai's henchmen to bring them back home. The rescue sharpens the stakes and confirms Honai's vendetta extends beyond the four friends alone.

Andrews' mother finally learns of her son's death and the wider backstory from Annie, who presents the key documents and the tangled history of the briefcases. The family tragedy binds the living to the criminals' loot and the lies surrounding the four friends. The revelation reframes the conflict as a legacy of vengeance rather than a mere misunderstanding.

In the tense climax, Honai chases the group to seize the case, but a fuse is pulled and a gas stove is lit by accident. A deadly fire consumes the house, and Honai dies in the blaze, removing the immediate threat. The truth about the ill-gotten money remains unresolved, but the danger has ended.

Maya and her grandparents return to Kannur, closing the chapter on Harihar Nagar. The four friends finally open the real briefcase and discover riches, ending the film on an unexpected windfall. They face an uncertain future with newfound wealth and a changed outlook.