Peter Sanderson (Steve Martin) is a workaholic tax attorney, separated from his wife Kate (Jean Smart) and often too busy for their children, Sarah (Kimberly J. Brown) and Georgie (Angus T. Jones).
Peter arranges a blind date at his home with Charlene Morton (Queen Latifah), a woman he has been chatting with online. Misled by her photograph and description, he is shocked to discover that she is actually a felon who corresponded with him from prison. Charlene tries to blackmail Peter into clearing her name of armed robbery, claiming she is innocent, but he throws her out after several attempts.
Just as Peter is about to meet with a difficult client, Mrs. Virginia Arness (Joan Plowright), he is ambushed by Charlene, who draws the lustful attention of his friend and colleague Howie Rottman (Eugene Levy). Agreeing to help expunge Charlene's record and let her stay at his house, Peter lies that she is his nanny. Charlene is disrespected by Kate's unpleasant sister, Ashley (Missi Pyle), but subdues her in a vicious locker-room brawl.
Peter takes Charlene to dinner, and Kate is upset to spot them dancing together. Returning home, Charlene coaches a drunk Peter on winning Kate back, and they are caught in a compromising position by Peter's bigoted neighbor, his boss’ sister. Charlene helps Georgie overcome his struggles with reading, rescues Sarah from unwanted advances at a party, and guides Peter toward becoming a more understanding parent.
Impressing Kate with his new commitment to spending time with their kids, Peter attempts to invite her over but is interrupted by a call, to Kate's disappointment. He races home to meet Mrs. Arness, who invites herself to dinner and reminisces fondly about her family's degrading treatment of black servants, angering Charlene. A TV news report declares Charlene a fugitive, having broken out of prison, and includes security footage from a bank robbery, appearing to prove that a masked Charlene committed the crime.
Mrs. Arness leaves, refusing to sign the lucrative contract for Peter's firm, and Peter sends Charlene away. At the office, he discovers Mrs. Arness has notified the FBI, and sneaks out to his car. He is threatened at gunpoint by Widow, Charlene's ex-boyfriend, who warns him not to reopen her case, but Peter manages to drive off. Realizing Widow must have framed Charlene, Peter returns home to ask for his children's help finding her.
Sarah admits that she gave Charlene his cell phone, which Peter calls and picks Charlene up. He explains that she was set up by Widow, who is likely at a club downtown. Peter drops Charlene off at his house, saying he is returning to the office, but instead goes to the club. Buying street clothes off of a passer-by, Peter enters the club in disguise. Kate arrives at Peter's house to find the children waiting while the FBI search the premises.
Charlene calls Howie to drive her to the home of Mrs. Arness, who refuses to let Charlene explain herself, leading Charlene and Howie to kidnap Mrs. Arness and her beloved French bulldog. Charlene calls Sarah and realizes Peter went to the club, where Peter attempts to blend in but is captured by Widow.
Peter gets Widow to confess to having committed the robbery disguised as Charlene. Arriving at the club, Mrs. Arness gets drunk and high while Charlene calls the authorities, and she and Howie confront Widow. After a scuffle for his gun, Widow shoots Charlene, and the FBI storm the club. Charlene is saved from the bullet by Peter's titanium cell phone, and Peter reveals that he recorded Widow's confession on a boombox, leading to Charlene’s exoneration and Widow’s arrest.
Having secured Mrs. Arness as a multibillion-dollar client, Peter and Howie start their own firm. Moving into their new office, Peter is surprised by Charlene, and they exchange thanks for their impact on each other's lives. Kate arrives, and she and Peter reconcile as his cell phone rings. He tosses it out the window and they kiss; downstairs, Charlene and Howie appear to do the same.
Steve Martin as Peter Sanderson,
Queen Latifah as Charlene Morton,
Eugene Levy as Howie Rottman,
Kimberly J. Brown as Sarah Sanderson
Angus T. Jones as Georgie Sanderson
Joan Plowright as Virginia Arness,
Jean Smart as Kate Sanderson
Missi Pyle as Ashley
Steve Harris as Widow
Michael Rosenbaum as Todd Gendler
Betty White as Mrs. Kline
Jim Haynie as Ed Tobias
Matt Lutz as Aaron
Victor Webster as Glen
Kelly Price as herself