Kaappaan (transl. Protector) is a 2019 Indian Tamil-language action thriller film directed by K. V. Anand and written by Pattukkottai Prabakar. It was produced by Lyca Productions and stars Suriya, Mohanlal and Arya in lead roles along with Sayyeshaa, Samuthirakani, Poorna, Boman Irani and Chirag Jani in supporting roles. The narrative revolves around a Special Protection Group (SPG) officer who struggles to protect the Prime Minister from a mysterious man who threatens to assassinate him.

The film was released theatrically on 20 September 2019 and received mixed reviews from critics. The film grossed ₹100 crore at the box office. It was the final directorial work of K. V. Anand, before his death on 30 April 2021.

Terrorists tried to kill the Prime Minister of India, Chandrakanth Varma, in New Delhi, but security services were able to stop the attack, save the PM, and send him to his office. The government used NSG operations to prevent the assassination. However, the Minister for Communications, Vasudev, was killed as collateral damage, and his daughter Anjali is the PM's junior office secretary.

Kathiravan "Kathir" is an organic farmer in Thanjavur who secretly works for the country's military intelligence. The SPG asks him to help protect the PM during his visit to London after a captured terrorist reveals a plot to assassinate him. Kathir identifies and shoots the suspect. Anjali, who mistakes Kathir for the assassin, tries to follow him, but he tricks her into getting drunk and loses her. Varma goes to India and discovers that the Pakistan army killed the Indian soldiers in Kashmir. Rajan Mahadev, a business tycoon and a public figure, meets Varma to discuss ways of retaliation.

Joseph, Kathir's co-worker and friend, gets a death threat during Joseph and Priya's wedding anniversary celebration. Suddenly, a sniper kills his pet cat. Kathir and Joseph try to track the killer, but he diverts them by murdering the sniper with a small bomb blast and escapes. Varma goes to Kashmir to speak to the public, but a mysterious caller interferes with the communication system of the SPG and alerts them to a bomb on the stage where Varma is speaking. Kathir discovers the bomb and throws it away. However, the caller uses the distraction to detonate another bomb in Varma's car, killing him. After Varma's death, there is a struggle for the position of the next PM, but Varma's advisor chooses his son, Abhi, to prevent a political divide.

Kathir gets suspended for failing to protect the Prime Minister. He discovers evidence that links their friend Ranjith, a disgraced double agent, to the killer. Ranjith seeks revenge on Varma and the SPG for his arrest, which led to his family's suicide. In addition, farmers are protesting against the construction of mines in Thanjavur, which are destroying their crops. Abhishek plans to close the mines, but Mahadev, the owner, opposes his decision, resulting in a political conflict. Despite security warnings, Abhishek takes Anjali out for her birthday, and there is an assassination attempt on him that injures Anjali. Joseph dies while trying to save Abhishek. Kathir gets angry at Abhishek for going outside with no security.

During the post-mortem, Kathir finds that one of his officers, Prem, has tried to tamper with the evidence. Prem reveals himself as a double agent who is in cahoots with Ranjith and was the one who killed Joseph while he was rescuing Abhishek. Meanwhile, male caelifera locusts suddenly infest the fields in Thanjavur. Mahadev orchestrated the outbreak since the farmers didn't give up their land for his mining company. Mahadev is also the brain behind Varma's assassination, and Ranjith and Prem are simply his puppets. Abhishek and Mahadev discuss this ongoing feud and agree that in the immediate press conference, Mahadev agrees to shut down his mines in Thanjavur. Mahadev seemingly agrees but secretly plans to release both male and female caelifera, which will ensure the destruction of the crops without any chances of revival and allow him to establish his mining company without further problems.

Kathir figures this out and destroys the train transporting the locusts, killing all the locusts. Ranjith enters the control room at the press conference and plans to kill Abhishek on Mahadev's orders. Kathir beats up Ranjith, who reveals that the bomb is with Anjali. Kathir calls Anjali to the control room, and they find that the cast on her broken arm contains the bomb. Kathir removes Anjali's plaster cast and disposes of the bomb. Kathir rushes to protect Abhishek but Ranjith says that Kathir's jacket has a bomb, and removing it will cause it to detonate. With Kathir frozen on the spot, Ranjith and Mahadev escape, enter the latter's car and detonate the bomb, but the bomb explodes in the car, thus killing Mahadev and Ranjith on the spot. In a flashback, Kathir had found the bomb in the jacket earlier and left the bulletproof vest in Mahadev's car. In the end, Kathir and Anjali are seen having romantic moments in his hometown.