Plot

Determined to make his town crime-free, Cop Arjun Pataila teams up with his quirky sidekick, Onnida Singh. However, his mission takes an unexpected turn when he falls for Ritu, a news reporter.

Arjun Patiala(Diljit Dosanjh)has recently been initiated into the police service. A man who has spend most of his early life disciplining himself in Judo and getting into the forces now decides its time to take it easy. He's introduced to his loyal "chita munshi" who soon turns into a confidant- Onida Singh. ( Varun Sharma) We quickly realise Arjun Patiala's quirks - That he is fond of women, and even fonder of his drink. But his quirky, original and unusual ideas help him reduce the crime rate in the city without even moving a finger. Along the way Arjun falls in love with a firebrand news reporter - Ritu Randhawa (Kriti Sanon) who might pull the curtain on his deeds. A laugh riot film, Arjun Patiala will leave you in splits.These unforgettable characters are definitely here to stay.

A director meets a producer, and he queries about all elements of a Masala film (songs, villain, fights, comedy scenes, etc.) and approves it without even reading the script. The director insists on reading out the script to him, to which the producer agrees. The script is about Arjun Patiala.

Arjun Patiala (Diljit Dosanjh) has recently been initiated into the police service. A man who has spent most of his early life disciplining himself in Judo and getting into the forces now decides its time to take it easy. As a reward, he is offered the post of an Inspector, and he takes charge of Ferozpur police station.

He's introduced to his loyal "Chita Munshi" who soon turns into a confidant- Onida Singh (Varun Sharma). He earns the respect of his colleagues on the first day with his wit and integrity. DSP Amarjeet Singh Gill (Ronit Roy) is Arjun's childhood hero and Idol. Arjun is corrupt and collects protection money from all local businesses. Arjun's father (Ritesh Shah) and Arjun's mother (Nirmal Rishi) encourage him to serve the poor and win hearts.

Arjun Patiala has many quirks - That he is fond of women, and even fonder of his drink. But his quirky, original and unusual ideas help him reduce the crime rate in the city without even moving a finger. Onida converts to Arjun's way when he sees that Arjun is trying not to stop crime but to reform potential criminals by teaching them good manners. The next day DSP Amarjeet Singh Gill visits their police station and tells Arjun that crime free district is his dream. Arjun promises Gill to make Ferozpur crime free under his watch.

Along the way Arjun falls in love with a firebrand news reporter - Ritu Randhawa (Kriti Sanon) who might pull the curtain on his deeds. A local drug lord Baldev Singh Rana thrashes the constable from his station. Ritu expecting ignorance from the police for this incident, reaches the crime spot and berates the police for inaction. Arjun Singh also reaches the place and trashes the Baldev, and arrests him. Ritu is impressed, and they start dating.

Ritu shares the list of all criminals with Arjun. Baldev Rana (Amit Mehra) is a drug mafia and civil contractor whom Arjun has beaten up already. She explains to him of rivalry between Baladev and Dilbaugh and Sakool, an emerging crime lord. Dilbaugh Singh (Himanshu Kohli) who owns Ferozpur crime businesses. Dlibaug and Baldev hate each other. Sakool (Mohammed Zeeshan Ayyub) and brother Anda (Sumit Gulati) runs a money lending business in the area and specializes in collections.

Editor (Biswapati Sarkar) has a crush on Ritu and keeps asking her to come home to meet his mother. DSP Gill introduces Arjun to MLA Makkad, who also appears to be upright and supports their action. MLA Prapti Makkad (Seema Pahwa) has the nickname "Property Makkar". Ritu hates gun violence as her family is also a victim.

With limited resources and legal constraints, Arjun decides to instigate a gang war among the gangs, which is the only way to eliminate the criminals. He gives Sakool the location of Baladev, and he kills him in the presence of roadside vendors and Arjun Singh. At media briefing, police claims there were no witnesses. Ritu believes that there have to be witnesses because the murder occurred at a busy street, she investigates and smells something fishy. She meets Arjun and expresses her concerns, and asks him to be honest with her. He lies to her that he has no role to play in this.

This sparks off a revenge killing spree between Baldev and Dilbaug's gangs and Baldev's gang is practically wiped out.

Ritu suspects that Arjun is up to some shenanigans, but Arjun convinces her. Now Arjun gets Sakool to send Anda to prison to kill Dilbaug, in which he succeeds. But then Arjun gets Anda poisoned inside the prison before he can escape.

Ritu is suspicious of all these gang wars and finally confronts Arjun. She offers him 2 choices, either she investigates all the killings, or they separate, which leads to their break-up. She meets Sakool and tells him about her suspicions, and tries to alert him of his possible death. Sakool tries to kill her because of her intricate knowledge of the crime world & she can become a possible witness to his plan of double-crossing the Police, but somehow she manages to escape.

Onida realizes that editor is keeping Ritu under video surveillance. He trails editor to find that he is working for Prapti who wants Arjun to eliminate all criminals so she can have complete control over the area and all criminal activities in it. Onida also finds that Gill is working for Prapti, who will kill Arjun once Sakool is taken care of. Realising they are being toyed, he tries to alert Arjun. However, his cover is exposed, and he has to run for his life.

Onida wants to warn Arjun, but Prapti and Gill convince Arjun to join their side. The trio (MLA, DSP & editor) visit Arjun Singh, and Makkad gives him an ultimatum to kill Sakool and Onida. She further tells him that she would personally inspect their dead bodies in the morgue. Arjun calls Onida & asks him to meet near a bridge and shoots him in front of Makkad.

Later in the day, he calls her to the morgue to inspect the bodies of Sakool & Onida. When she arrives at the morgue, Sakool and Onida shows up alive, and Arjun has double-crossed both Makkad and Sakool. There is a fist fight at the scene, and Arjun is able to escape with DSP Gill and Onida. Sakool and Makkad also escape in the morgue van. Sakool chases Arjun to his ancestral home, and after a long cat and mouse chase, Sakool is shot dead when his father accidentally fires Arjun's gun.

Makkad is sent to jail, Arjun and Ritu reconcile.