Regan Madison is the only daughter of a wealthy family. She and her three older brothers were raised by nannies and today run the family business, a chain of luxury hotels. Regan returns to her hometown of Chicago after an extended business trip and meets her two childhood friends, one of whom is a reporter, for lunch

To help gather information for a big story, Regan and her friends attend a seminar conducted by Dr. Laurence Shields, a self-help guru, whom they suspect of taking advantage of wealthy, vulnerable women. During the seminar, Shields asks the participants to make a list of people they'd be happy never to see again. Some of the participants jokingly call it a 'murder list.'

Regan halfheartedly makes a list, expecting to burn it in the fireplace after the exercise. But an ill-timed phone call leaves her still holding her list after the seminar is over. Returning to her car that night, Regan is accosted in the parking lot. In her haste to escape, she twists her knee and collapses, dropping her purse, cell phone and the contents of her seminar folder. Within days, Regan begins receiving emails and faxes containing photos of the people on her 'murder list.' They are all dead.

Alec Buchanan is a police detective who has recently resigned and is working out his three-week notice before joining the FBI. Having drawn the ire of his Lieutenant, who is hoping to curry favor with Regan's brothers, Alec is assigned to provide bodyguard services for Regan.

Thrown together all day, every day for an extended period of time, Alec and Regan discover they enjoy each other's company, and an attraction begins to grow between them. At first, neither of them acts on the attraction, both knowing Alec is leaving Chicago soon.

Just before Alec's three weeks have ended, he and Regan give in to the attraction and spend the night together. Afterwards, Alec tells Regan it can't happen again. He's going to Boston and starting the next phase of his life. Regan is heartbroken but determined not to let it show.

A man who is angry with Regan for denying his grant request makes a threatening phone call to her, and is arrested. At his house, police find evidence implicating him in the murders. Regan's security team is called off and Alec prepares to leave Chicago. After a sleepless night, however, he realizes he is in love with Regan and doesn't want to leave town unless she is with him.

He goes to her office to tell her about his change of heart. On the way, he receives information about the real killer. Regan's brother, Walker, had been involved in a serious car accident two years earlier. In the accident, the killer's wife was seriously injured, losing the use of both her legs.

Although Walker was absolved of any blame in the accident, the killer and his wife, Eric and Nina Gage, turned their anger and bitterness towards Walker and are now going after Regan in revenge. Alec rushes to Regan's office but she isn't there. He does, however, find another fax. It is a second murder list and, this time, Regan's name is on it.

At the local park, Regan is participating in a charity run. Due to her knee injury, she is unable to keep up and is quickly separated from her friends. Deciding to return to the parking lot, she takes a shortcut through the woods - and is confronted by the killer.

Alec arrives at the park just as the first shots are fired. He charges into the woods but Eric Gage hears Alec's approach and is waiting for him. Before the Gage can fire, Regan launches herself out of her hiding place in a tree and knocks him down. Alec finishes the job with one shot. At the Gage home, Nina commits suicide when she realizes her husband failed to carry out her wishes.

Alec finally gets a chance to tell Regan he loves her. Obviously, she returns his feelings. She turns her Chicago office over to her assistant and begins working out of her family's Boston hotel so Alec can begin his career with the FBI.