The film begins close to the end of the story, when the suspects get caught and are interrogated. Then it flashes back to three years earlier and proceeds forward from there, interspersed with occasional bits from the interrogation.
Three years before getting caught, Bridget (Diane Keaton) lived a comfortable life until her husband Don (Ted Danson) was fired from his position and sunk into debt. The paycheck for Selina, the cleaning lady, bounces again. Selina confronts Bridget and suggests she take a job as a janitor at the Federal Reserve Bank of Kansas City.
On her first day on the job, Bridget hatches a scheme to steal damaged dollar bills slated for destruction. For her team she chooses Nina (Queen Latifah), who works the dollar bill shredder, and Jackie (Katie Holmes), who takes bill carts from the Secret Service room to the shredding room. It takes some work to convince Nina to join, but Jackie joins them quickly.
The plan is that in the Secret Service room, Bridget will switch a cart's official Master-brand lock with a near-identical lock she purchased at Home Depot. Bridget will tell Jackie the cart number and give Nina the official lock. When Jackie gets the chosen cart, she dumps some bills from it into a trash can before taking it to Nina, who then uses Bridget's key to open it, replaces the official lock, and proceeds to shred the remaining bills. Meanwhile, Bridget, in the course of her janitorial duties, retrieves the dumped bills from the trash and splits them among Nina and Jackie in the restroom.
While a success, the take from their first robbery is not as big as they had hoped. However, they're emboldened to do it again and again. Once Don and Bridget pay off their debt, Don suggests they stop before they get caught. Bridget rejects this idea and convinces Nina and Jackie to keep going. They almost get caught, but they fold in one of the cops.
A Federal Bank Examiner shows up at a party at Bridget's house, and the next day Bridget sees him at work. The Examiner confronts Glover (Stephen Root), who is unwilling to admit anyone has stolen a single bill out of his bank as a matter of professional pride. Tipped off, that night Bridget and her accomplices begin trying to get rid of all the loot stashed in their houses, but the cops move in before all the evidence is destroyed. Bridget escapes but the others get caught.
Bridget hires a tax attorney to defend them, and he gets Bridget and all her accomplices off the hook for their crimes. However, the IRS demands they pay their taxes, which turn out to be equal to the money that remains. They walk away free yet penniless.
Eight months later, Bridget reveals to Nina and Jackie that she stashed away a lot of the stolen money in the basement of a friend's bar.