The film opens with Danny (Zayed Khan) boarding an plane. A girl named Ria (Ayesha Takia), enters the flight, talking very loudly and rudely to a somebody on her phone, irrationally arguing as to why people should not travel on aeroplanes. She even mistreats the cabin crew and casually asks Danny to put something in her bag. Seeing an opportunity to talk to her as they are both alone in the business section of the flight, he introduces himself as Dhananjay Jumbevalkar and craftily manages to engage her in a conversation and they decide that over the course of the journey, he will tell her a story of three unique diamonds worth 200 carats each.
The story begins in 1836 where a miner in Southern India finds a diamond as he mines coal. The miner gives the diamond to his king, who in turn gives it to an English viceroy. However, the ship in which the Viceroy is travelling sinks and the diamond, too, is lost at sea. Many years later, the diamond is found by a fisherman in Bulgaria, who gives it to the ruler. The ruler decides to give three pieces of the diamond to his three sons but one of them loses it by gambling, an Australian army officer takes the second piece and the last one is taken by a unidentified man, who steals it from him. Many more years later, the diamonds resurface again in 1994 where a gangster sells the two pieces to a man known only as Uncle. However, they are unaware that there was a third piece, which has surfaced only recently.
A businessman calls the Indian Intelligence Unit in Cape Town, South Africa, and asks for protection as he takes something valuable, most probably the diamond, from one place to another. Shanaya (Shamita Shetty) is assigned to the case. However, in transit, the diamond is stolen by henchmen working for a Chinese gangster. Their rival, Uncle, another influential gangster, wants all the diamonds for himself. One of Uncle's trusted aides, Angad (Sunil Shetty) had been shot and betrayed by the former into going to prison. Now, as he is released, he volunteers to steal the diamond for Uncle, who does not trust him. Angad meets his old partner Aditi (Dia Mirza), for the job and asks her to provide a team of the quickest, fastest and most unbeatable, thieves ever. Aditi decides to meet Doc (Ajay Devgn), the leader of a gang of thieves. Doc had been an engineer who specialised in making weapons. He has no real name or identity. Doc is also masquerading as Karan, a writer, who is Shanaya's boyfriend, with her being unaware of his true identity. The job Aditi tells Doc about involves stealing a painting from an art gallery and then delivering it to a yacht. The payment would be 4 million dollars
Doc says that two people are needed for such a job. The first he recommends, is Lucky (Ritesh Deshmukh), an expert on skateboards and parachutes. The second is Danny (Zayed Khan), an expert in water sports. However, the two hate each other to the core and always, often comically, find themselves in the same place, completing the same heist. However, to keep both of them at bay, Doc, hires Pooja (Esha Deol), another thief who worked with Danny and Lucky as a partner, and with whom both of them were in love at a given point of time. Pooja barely manages to keep them both at bay as they try to meet her, once again, at the same time. The plan is laid out. Lucky would walk into the art exhibition and steal the painting, escaping on the road. Lucky is then asked to throw the painting into the water at a stipulated point, where Danny would pick it up and deliver it to a yacht. Lucky and Danny would both be given 2 million dollars for the job, each. At the same time Doc would steal this money from a convoy belonging to an unknown drug lord named Hafeez Bhai.
The plan works as per requirement and all the three stages are successful. However, this heist only turns out to be a distraction for a bigger one that Angad had had in mind earlier. With the painting being robbed, Angad, who wants the diamonds for himself, would have enough time to steal the diamonds from Uncle's boat. He betrays Uncle, kills him for his betrayal and escapes from the boat. In the confusion, Aditi steals the money for the diamonds from Uncle's vault on the boat, which she then uses to make the deal with the Chinese gangster who had stolen the last and final piece, thus acquiring all three pieces
There is a set up however, since the armoured convoy Doc is robbing turns out to be a cover for a police team headed by Shanaya. Even though he manages to escape with the money, it is later revealed that the money that Doc had stolen from the convoy was marked. Angad had set them up, knowing well that the armoured convoy was a police team. Aditi had made the deal for the last piece of the diamond, going in place of Shanaya, who would have been stopped by Doc's robbing of the money she was carrying. Aditi is unaware of Angad's true motives, and she is set up as well after the Chinese Mafia she made the deal with is caught and reveals all the information about her.
Doc then books a yacht which he pays for with the marked money, for a birthday party for Shanaya (he plans to propose to her). Over phone, Shanaya informs him that the money was marked and had just been spent for a party on a yacht. He rushes back, just in time, to prevent the manager of the yacht from revealing his real identity to her. Later on, the police have used the information on Aditi and have already made sure that she does not leave the country with either the diamonds or the money. Doc, who has realised that the job was a set up, calls Aditi and informs her that the police have information about her, including the number of the flight she was supposed to be leaving the country on, all the time expressing anger that she had trusted someone like Angad, who had betrayed not only Doc's team, but her as well. Aditi hides the diamonds in her car, confronts Angad, who does not deny setting her up along with the others, and escapes to a casino, where she runs into Lucky, who is there to spend his money to gamble. While they collide with each other, she discreetly exchanges her car keys with his, before being captured by Angad, who shoots her dead after a further confrontation. Doc, finding Aditi dead, gets a call from Angad, who demands that his diamonds be given back. Danny, who is at the airport with Pooja, gets a call from his friend, to whom he had given his share of the money to send to India, informing him that the money is marked. Sensing Pooja's desperation at this fact, he goes with her to save Lucky, who escapes with their help after a car chase and a gun fight. The trio then get together and confront Doc and find out the truth about the set up. While Doc says that the diamonds are in Aditi's car, the team is unaware that Lucky has it.
After a bomb scare which was supposed to kill Shanaya, Angad now gives Doc a limited amount of time to give him the diamonds. The group first save their skins from Shanaya and the police by storming into the hospital and scaring the injured and terrified yacht manager into silence about Doc's identity. However Shanaya is captured by Angad's men, and is being led away in a convoy, which is disguised as a police team. A separate convoy contains the car, which contained the diamonds, and which had been taken away as the group had realised that they had had it. Angad calls again and demands the diamonds in lieu of Shanaya's life. The group is forced to formulate a plan then and there. They first change the traffic lights and also stage a traffic jam so that both convoys can change to routes that they desire, with the idea being that they would have to travel outside city limits.The team uses this change of route to its advantage. Doc and Lucky intercept the second convoy, blowing up the rest of the cars and acquiring the car containing the diamonds, while Danny and Pooja intercept the first, with Pooja saving Shanaya's life. Doc, Lucky and Danny, then go to confront Angad. While Danny and Lucky beat up Angad's henchmen, Doc confronts Angad and the trio shoots him dead for betraying them and Aditi.
It is here that the flight lands and Ria and Dhananjay exit the plane to be met by the members of the group, including Doc. It his revealed by Doc here that "Ria", was actually Preeti, a new member in their group. Dhananjay now laughs at the fact that she knew him to be Danny all along. At this, Shanaya arrives, apparently still unaware of Doc's real identity. Smiling, the group then leaves the airport while Doc muses to Shanaya about another diamond in a nearby museum, possibly hinting at another heist.Ajay Devgan as Karan aka DocSuniel Shetty as AngadEsha Deol as PoojaRiteish Deshmukh as Lucky, a small-time thief who is an expert on Skateboards and parachutesZayed Khan as Dhananjay Jhumbevalkar aka Danny or DJ, and expert on water sports.Shamita Shetty as Shanaya, Karan's girlfriendDia Mirza as Aditi, Angad's girlfriendAyesha Takia as Preeti/RiaAmrita Rao as KiranBruna Abdullah in a Special Appearance in Item Song "Reham Kare"
The film received mixed reviews from critics. Taran Adarsh of Bollywood Hungama rated the movie 3 out of 5 saying "Cash has all merits to strike a chord with the youth", praising Ajay Devgan's 'bravura' performance, the film's 'Hollywood style' look and action sequences, as well as the music. Noyon Jyoti Parasara of AOL India gave 3 out of 5 to the film saying, "once you are willing to let go off your beliefs and logic – like you really can’t jump off a cliff on your bike and remain unscratched – you would like the film."
On the other hand, Omar Qureshi of Zoom rated the movie 2.5 out of 5 saying, "The film is over the top and unrealistic." Indiatimes.com rated the movie 2 out of 5 stars saying, "The film has taken the audience for granted, which shows us gadgets hard to believe and futuristic and that such futuristic shows should be limited to Hollywood.". Subhash K. Jha gave the film 2 out of 5 stars, and said, "Cash wears its super-cool shirt with the slogan ‘Come Watch Me’ with a little bit too much aggression. But if you love popcorn crunching adventure stories watch Ajay Devgan play the hero from the hemisphere of hijinks." He praised Devgan's acting and the action sequences, saying that "To his credit Devgn carries off the ceaseless stint with the stunt with arresting aplomb[...]The expertly-executed stunts frequently see our hero jumping down high-rise buildings in breathtaking leaps of fate, with the camera pulling back in respectful awe."
According to Channel V, the film wears a bad look, has little good locations, but is 'nil' on the acting quotient. In their opinion, none of the heroines delivered performances worth even a mention. On the other hand, they did say that Ajay Devgan delivered a good performance. They also said that the action is beyond belief and is unreal.
The film performed reasonably well during the first week upon its release, however its business fell by around 80% in the second week, largely attributed to its huge price tag. The film was declared a flop by the Box Office India.
The soundtrack of the film composed by Vishal-Shekhar. The Song "Raham Kare" has been penned by Panchhi Jalonvi, and all other songs are penned by Vishal Dadlani. According to the Indian trade website Box Office India, with around 12,00,000 units sold, this film's soundtrack album was the year's ninth highest-selling.