"Every day without fail, Travis Devine puts on a cheap suit, grabs his faux-leather briefcase, and boards the 6:20 commuter train to Manhattan, where he works as an entry-level analyst at the city's most prestigious investment firm. In the mornings, he gazes out the train window at the lavish homes of the uberwealthy, dreaming about joining their ranks. In the evenings, he listens to the fiscal news on his phone, already preparing for the next grueling...

Rachel is unemployed and devastated by a recent divorce. She fills her time with drinking, riding the commuter train, and fantasizing about a seemingly perfect couple the train passes by every day. Then one morning, Rachel sees something shocking that unravels her and entangles her in an unfolding mystery.