After her estranged sister is killed when she falls onto the subway tracks in Paris just as a train arrives, Allison goes to Paris to deal with her sister's body and collect her things. But, after talking to the police about the accident and viewing the subway surveillance video, something seems odd about her death. When Allison's hotel room in Paris is broken into with only a few things taken, but not any money or credit cards, she begins to wonder if it really was an accident that killed her sister, or if it was murder. Once Allison returns to Washington, D.C. to handle her sister's affairs, she soon realizes that her sister had been living a secret life and wasn't the person she had always thought she was. As troubling things begin to happen to Allison in D.C., she starts wondering if she will be the next person to die.