Jessica Martin (Kim Basinger), a high school biology teacher, takes her son Ricky to his bus stop for school. After she returns home, several men break into her house, kill her housekeeper, and confine Jessica in the attic of their safe house. Ethan Greer (Jason Statham), the group leader, smashes the attic's telephone. Jessica uses the wires of the broken phone and randomly dials a number. She reaches the cell phone of Ryan (Chris Evans), a carefree young man who has just been dumped by his girlfriend, Chloe (Jessica Biel).
Jessica persuades Ryan to go to the police station, where he briefly reports to Mooney (William H. Macy), but has to leave to avoid losing connection. Ethan asks Jessica about something, which she denies knowing, and leaves to get Ricky. Overhearing them, Ryan gets to Ricky's school, only to see the boy kidnapped. He hijacks a security officer's car and gives chase. When his phone battery runs out, he takes the gun in the car, cuts in line at a shop and buys a charger.
Deciding to check on Ryan's kidnapping claim, Mooney goes to Jessica's house. At the house, he finds Dana Bayback (Valerie Cruz), the kidnappers' accomplice, posing as Jessica. Believing the claim is a false alarm, Mooney leaves. With Ricky in tow, Ethan returns and asks Jessica about a place her husband Craig mentioned, "The Left Field", and learns that it is a bar at the Los Angeles International Airport.
A cross-connection between phone lines causes Ryan to rob a nearby lawyer's cellphone and car. The lawyer refused to believe that Jessica was actually kidnapped. At the airport, Ryan plants the gun on one of the kidnappers, which trips the alarm. When security intervenes, the kidnappers are revealed to be police officers and they proceed to apprehend Craig. After viewing a news report of a man holding up a store for a charger, Mooney identifies Ryan and calls Jessica's home. He notices the voice on the answering machine is different from that of the woman he met.
The kidnappers learn that Craig put his bag in a bank safe deposit box. One guards Jessica and Ricky, while the rest go to the bank. Ryan finds the box first and leaves with Craig's bag, but loses the lawyer's cellphone. When Ryan opens Craig's bag, Ryan finds Craig's video camera. Craig accidentally filmed LAPD Detectives Ethan, Mad Dog, Dimitri, Bayback, Deason, and Jack Tanner (a friend of Mooney's) robbing and murdering two drug dealers, revealing that they are dirty cops.
Ryan steals the lawyer's car from the impound lot and retrieves his own cellphone. Mooney returns to the Martin residence, where Bayback injures him. He kills her and learns that she is also a cop. Back at the safe house, Mad Dog learns that Jessica has been trying to contact help and attacks her. Jessica—being a biology teacher—purposely cuts his brachial artery, and he bleeds to death. Before Jessica and Ricky can escape, Ethan's gang returns. Ryan contacts Ethan and makes a deal: the videotape in exchange for the Martin family at the Santa Monica Pier.
Tanner convinces Mooney to go to the pier to identify Ryan. Ryan disguises himself, but is inadvertently exposed by Chloe and identified by Mooney. Tanner sends Mooney away for medical attention, arrests Ryan and brings him to Ethan. Ethan destroys the videotape, and Tanner radios the order to kill the Martins, however, Mooney overhears the radio transmission. Ryan escapes, following a distraction by his friend Chad. Mooney overpowers Dimitri and handcuffs him then returns to the pier. Tanner and Ethan confront Ryan in a boathouse. Ryan knocks out Tanner. Unfortunately, Ryan is outmatched by Ethan. Ryan punches Ethan a couple of times in the stomach. Ethan tries to kill Ryan, but Mooney shows up. After a brief chase, Ryan notices Ethan has circled behind Mooney, and calls Ethan's cell phone. The phone's ring betrays Ethan's position, and Mooney promptly shoots him to death.
Jessica strangles Deason with her handcuff chain in the van, then frees her husband and son. However, Deason was merely stunned, and aims his gun at them. Ryan intervenes and knocks Deason unconscious. While Ryan and Mooney are being treated by medics, Tanner is also exposed, because Ryan had copied the video recording onto his cellphone, and the Martin family is set free. Jessica finally meets Ryan, the man who risked his life to save her family. When she tells him she doesn't know how to thank him, Ryan humorously tells her to not call him again.
Larry Cohen, screenwriter of the 2003 thriller film Phone Booth, conceived of Cellular while working for Sony Pictures. Cohen's original screenplay mimicked Phone Booth by its theme of a "narcissistically obsessed society" enamored to their cell phones. Its story followed a 30- or 40-year-old man named Theo Novak who obtains a call from a woman named Lenore, who tells him that she and her husband have been abducted in a safehouse by a group of bank robbers. It is then revealed that Novak is an art thief who becomes wracked with guilt after unsuccessfully rescuing a friend from committing suicide in the past; he agrees to make a detour from a criminal undertaking and rescue Lenore. During the rescue Novak is unsuccessful, but later discovers a conspiracy involving Lenore and her accomplices over another crime they are involved with—ultimately, Novak gains the upper hand, killing Lenore and her accomplices and obtains their loot in the process, which leaves him therefore a wealthy man.
Sony Pictures' then Vice President Lauren Lloyd was drawn to Cohen's script and thought of pitching it to fellow executives, but was unsuccessful in doing so. She then left Sony to produce the project independently. Lloyd sent the script to her colleague producer Dean Devlin and pledged to develop it together. Aiming for a story straightforward and devoid of bitterness and cynicism present in Cohen's version, the pair hired screenwriter Chris Morgan. Morgan had been passionate about crafting "a story about how an everyday person can become heroic when faced with a certain set of trying circumstances", and he incorporated that in Cellular. In an attempt to segue the script's predominant action and thriller elements with situational comedy, as well as appeal to young audiences, Morgan took inspiration from the comical attributes of the fictional character Indiana Jones:
I'm a big fan of situational humor and I feel like comedy plays best when it's the right thing at the right time and not just somebody trying to make a joke. For example, in Raiders of the Lost Ark when Indiana Jones is faced with fighting the swordsman and he just pulls out a gun and shoots him. That’s not really a joke, but it got a huge laugh. That's the kind of humor we tried to work.
The soundtrack for the movie was composed by John Ottman and released on October 5, 2004 via La-La Land Records label.
The film has had gross receipts of $32,003,620 in the U.S. and Canada and $24,419,067 in international markets for a total of $56,422,687 worldwide.
Rotten Tomatoes, a review aggregator, reports that 55% of 149 surveyed critics gave the film a positive review; the average rating is 5.8/10. The sites consensus states, "Though it's gimmicky and occasionally feels like a high-end cell phone ad, Cellular is also an energetic and twisty thriller." Metacritic, another review aggregator, gave the film a score of 60 out of 100 based on 29 critics, indicating "mixed or averaged reviews".
Entertainment Weekly called the film "pure chase-thriller excitement", and Claudia Puig of USA Today called it a "well-paced action film in the vein of Speed". Roger Ebert called it "one of the year's best thrillers".
A novelization of the film was written by Pat Cadigan and released in October, 2004 by Black Flame. Cellular was released on DVD along with the VHS format on January 18, 2005. The film was released on Blu-ray on July 17, 2012.
In 2008, Hong Kong remake of the film entitled Connected was co-written, produced and directed by Benny Chan. The film stars Louis Koo, Barbie Shu, Nick Cheung and Liu Ye.