Rachel takes the same commuter train every morning. She knows the train always has to wait at the same signal, overlooking a row of backyards. Over time, she's come to feel like she knows the people from one of the houses. She calls them "Jess and Jason." Their life seems perfect to her. If only Rachel could be that happy. One day, she sees something shocking. It's only a minute before the train moves on, but that brief moment is enough. Everything has changed now. Rachel has the chance to become part of the lives she previously observed only from a distance. Now they will discover that she is much more than just that girl on the train...