One 2 Ka 4

The film begins by introducing friends and co-workers Senior Superintendent of Police Officer Javed Abbas and Assistant Commissioner of Police Officer Arun Verma, who are both Special Task Force officers and partners. Javed is a widower who is bringing up his 4 children with love and effort while Arun is his carefree, hotheaded, albeit well-meaning subordinate and brother-like friend. Arun doesn't like Javed's four children, just like he doesn't like any child, nor do the four children like him.

KKV is a local drug lord that the entire police department have always been desperate to catch. Unfortunately, due to KKV's broad connection in the police department, nobody ever manages to find any solid proof against him.

With the help of an informer, police catch KKV's group red handed while he is dealing drugs. After he is caught, someone replaces the drugs detained from KKV with sugar, causing him to be released, making it very clear that someone in the police department is working for him. The Police Commissioner is eager to find the traitor.

Geeta is Javed's friend. Once she meets Arun, she falls in love with him at first sight, but Arun shows no special interest in her and always avoids her.

While on a subsequent drug raid, Javed is shot dead by an unknown assailant. Before the mission, Javed wrote a letter to Arun, asking Arun to take care of his four kids if he does not survive. As Javed's best friend, in spite of not liking kids, Arun decides to adopt Javed's children, instead of sending them to an orphanage. Arun also seeks help and refuge in Geeta, so that she can help him take care of the children. As their relationship develops and time goes on, Arun begins to develop feelings for her and he begins opening up to the children. Arun's life soon becomes difficult as his salary is not enough to support so many people.

In a visit to KKV's club to threaten him, Arun unexpectedly finds that Geeta is a dancer at that club. Arun becomes angry with Geeta, not only because he thinks being a bar dancer is a filthy job, but also because he thinks Geeta has been cheating him by pretending to be decent. When he returns home later, he confronts Geeta and questions her, but the children all say that Geeta was with them the whole day and never once left, leaving Arun to believe that the bar dancer is another person that simply looks like Geeta.

Under the pressure of his living situation, Arun robs KKV. He steals a large amount of drug money from KKV, knowing it's dirty money, and buys a big house for his family. Arun gets caught and arrested almost immediately, not for the robbery, but instead for illegal drug possession. He is charged with being KKV's spy as police identify that the drugs found in his house belong to KKV. Obviously, Arun is being framed by someone, as he never stole any drugs, but he does not know who framed him. During his court hearing, Geeta also testifies against Arun, however, not as his fiancee, but as a secret police officer who worked at KKV's bar—confirming that she was the bar dancer Arun saw—and the witness of Arun's robbery. Arun is therefore suspended from duty until further trial.

Arun now does not believe anyone anymore; he decides to find the killer of Javed and the spy for KKV on his own. At his house, he questions a police officer whom he believes to be corrupted. The officer admits he is a spy for KKV, but follows the order of JD, another police officer. He also says he does not know who killed Javed, but JD does. Arun kills him and heads for JD's house.

On his way to JD's house, Arun calls Geeta for help, who was with the Police Commissioner when answering the phone call. With the permission of the Commissioner, Geeta joins Arun to question JD, only to find JD was killed right before they arrive. They believe the Police Commissioner is the spy as he is the only third person that knows they are heading for JD.

Arun rushes to the Police Commissioner's house and thrashes him, but the latter denies being a spy for KKV. Geeta goes to CBI Chief's house to report the situation, who is the superior of the Police Commissioner, but she finds KKV is in the Chief's house with him; she immediately realizes that the Chief is the real spy as he might have known of the original plan from the Commissioner. The Chief and KKV try to kill Geeta, but she manages to escape.

Geeta visits Arun and the Commissioner and tells them her findings about the Chief. The Commissioner is shocked to know of this information, and tells the pair that the Chief is planning to leave the country very soon. Geeta and Arun quickly arrive at the airport to stop the Chief from leaving. During a gunfight at the airport, KKV kills the Chief while taking him hostage. Inspector Sawant kills KKV and gets killed by Arun. Sawant also reveals himself as the killer of Javed as he was always belittled by the latter and upset that Javed got all the credits and honors despite Sawant's hard work and dedication. After taking Sawant down and saving the day, Arun is later praised by his department, gets his job back, reunites with the children (who now love him for his character arc), and marries Geeta.

• Shah Rukh Khan as Assistant Commissioner of Police Officer Arun Verma
• Juhi Chawla as Geeta Chaudhury
• Jackie Shroff as Senior Superintendent of Police Officer Javed Abbas
• Nirmal Pandey as Krishan Kant Virmani (KKV)
• Dilip Joshi as Champak
• Rajendranath Zutshi as Sawant
• Akash Khurana as Police Commissioner Akash Khurana
• Keith Stevenson as CBI Chief
• Sahila Chadha as Bipasha
• Suresh Chatwal as Inspector Rajendra
• Madhur Mittal as Michael
• Fatima Sana Shaikh
• M. Rehman Naushad Ali as Broker
• Jack Gaud as Shetty
• Bharat Dabholkar as J.D.

A. R. Rahman composed the soundtrack of the film, and lyrics were written by Majrooh Sultanpuri and Mehboob.

• One 2 Ka 4 at IMDb