Helen Wilson is a bank teller in a small town in Wyoming. She does not have many friends, but she met a couple named Rhonda and Clyde Felson in a neighborhood coffee shop one day and hit it off with them. The Felsons invited Helen on a ski trip, although she had never skied before. Helen got injured and had to go on crutches. The Felsons take her to the hospital, and then take her home. Rhonda offers to call Helen's boss for her, which Helen agrees to right before she falls asleep.
Two of the town's detectives are at work on a typical day. Marcia, one detective, argues with Pearson, another detective, for giving an illegally parked car a speeding ticket, since she says that is not how they do things in their town. The two watch Roscoe, a Native American man who is banned from the reservation, fix the stairs of Maude, an elderly woman. Pearson says he cannot understand why Roscoe does the work for her, since she does not pay him.
The next day, the heat is broken at the bank where Helen works, so everyone is wearing jackets. "Helen" comes into work on crutches, and her face is bandaged. A man soon enters with duffel bags with the name of the town's casino on them. "Helen" deposits the money, but her boss Spencer cannot find her afterwards. Another banker says that the casino gives duffel bags to anyone who spends $50 on the slot machines. Spencer calls her cellphone, which she does not answer. Then, he calls her landline. Helen picks up the phone, and reveals that she has been at home all morning and never came into work, and that she broke her ankle and her face was not injured at all. Spencer finds stacks of fake bills under Helen's seat.
The detectives of the town, Marcie and Pearson, speak to Helen about Rhonda and Clyde, since at this point they have discovered that Rhonda impersonated Helen and her husband pretended to be from the casino. Helen reveals that the couple drove a Toyota to the ski area, but she saw that Clyde had keys for a Honda. They figure that the couple dumped the Toyota and are driving the Honda.

Rhonda took Helen's phone, but Helen's aunt is able to track it using her phone. The detectives realize that the couple must have cut the heat to the bank. Two state police detectives come to town to take over the case. They track Helen's phone to a motel. The town detectives Marcie and Pearson realize something is missing, and discover that a Honda they ticketed that morning was parked next to a ladder that lead to the bank's roof. The state detectives arrive at the motel and find the phone in a mailbox, with a note attached saying "adios." Rhonda and Clyde are across the street in a different hotel, watching the scene unfold. They are convinced they are safe, and plan to use the money to go to a tropical location. When they are about to get in their car to leave, Marcy and Pearson appear to apprehend them. Marcy reveals that they knew the couple was there because they knew what their car looked like from the parking ticket. They arrest the couple. Life returns to normal. Helen has a date with one of the state police detectives, and Pearson tells the bank that Maude, the old woman, and Roscoe, her helper, told him about Rhonda and Clyde's illegally parked car, so the two get the reward money although they were not involved.