Sahadevan is the son of a police constable, Prabhakaran, who works in the local police department’s dog squad. Their loyal dog, Arjun, is more than just a pet—he’s a trained part of the force, capable of sniffing out clues and helping to nab culprits. Sahadevan’s single dream is to join the Kerala Police, and he passes his exams and gears up for the physical test. Yet he clashes with his brother-in-law, Pitambaran—a Sub-inspector in the same force—because Pitambaran married Sahadevan’s elder sister after an elopement, creating family tensions that spill into his professional life.
A thread of danger widens when a terrorist leader, Khalid, known as “Baba,” sits in Tihar Jail and hatches a plan to wipe out the new Chief Minister, Ravi Menon. Baba enlists the help of a shrewd and corrupt Police Commissioner, Gowrishankar, to execute the attack. The plan hinges on a bomb planted inside the hospital where Chief Minister Menon is receiving treatment. Baba’s rebels—Randheer, Amar and Jandu—conceal the device, but Sahadevan and Arjun manage to locate and eject it, saving lives though Arjun is wounded in the process. Sahadevan also arranges urgent medical care to bring Arjun back to health.
In response to Sahadevan’s hospital heroics, the powers-that-be, led by Gowrishankar with Pitambaran’s help, hypocritically set him up to fail the upcoming physical test. Rather than give up, Sahadevan pivots toward a different calling: a private detective path inspired by his late uncle, Karamchand. Drawing on that family legacy, he adopts the pseudonym Moosa and begins a fresh investigation into the attack on the Chief Minister. This marks the birth of a new hero in the city: a self-made sleuth who uses wit, gadgets, and grit to track down leads.
Moosa’s first case pits him against the trio who planted the hospital bomb. He and his allies track down Randheer and surrender him to the police, earning the respect of the DIG, Sathyanath, who is Menon’s nephew. Yet the ever-calculating Gowrishankar quietly murders Randheer to silence the interrogation and even destroys Moosa’s improvised office when he discovers there’s no license backing the operation. The remaining two terrorists press a second threat, this time targeting Menon with another car bomb. Moosa acts quickly, attending to the Chief Minister and foiling the plan, and is hailed as a public hero for saving Menon’s life.
Meanwhile, Meena, the woman Moosa has been pursuing, reveals a crucial truth: Randheer, Amar and Jandu had been living as paying guests in her apartment, and she had filed a complaint when they disappeared. Although Meena is unaware of their identities at first, Moosa insists they’re terrorists and that Gowrishankar is behind the plot. Meena is arrested by Gowrishankar on false charges of harboring terrorists, prompting Moosa to plead for her innocence. He is turned away, but his tenacity pays off when Gowrishankar tortures Meena in an attempt to coerce a confession.
Moosa arrives in time to rescue Meena from the abuse, and she responds with a clear return of feeling. The confrontation tightens: Gowrishankar issues an arrest warrant against Moosa, approved by a reluctant Menon. Moosa slips into Menon’s house to plead his case once more, and Menon reveals he knows the truth about Baba’s involvement. The conversation triggers a violent turn as Baba and the commissioner converge in a climactic standoff.
In the ensuing confrontation, Moosa, Menon, and Arjun dodge pursuit through a high-stakes chase, leveraging his detective-car’s new pursuer-repellent gadgets to stay ahead of the law. The showdown reaches its peak when Baba and the commissioner close in, but Moosa’s quick thinking allows him to eliminate the threat and clear his name. With Baba and the corrupt commissioner defeated, Moosa is declared a hero by the public and authorities alike, and Menon’s trust in him is fully restored. Moosa and Arjun are sent to Scotland Yard for advanced professional training, signaling a new phase in his career.
Before departure, Moosa shares a heartfelt farewell with family and friends, including Sathyanath and Pitambaran, who pay their respects as he prepares to embark on this next chapter. Yet a final twist awaits: a lunatic from the earlier plot hijacks Moosa’s private jet, tying up the pilot and sending the aircraft into a perilous ascent before it vanishes into the clouds—leaving the door open for one last unexpected turn. The story closes on a note of suspense, even as Moosa’s legend as a detective grows.
