"It all happens so quickly. One day you're living the dream, commuting to work by ferry with your charismatic neighbor Kit in the seat beside you. The next, Kit hasn't turned up for the boat and his wife, Melia, has reported him missing. When you get off at your stop, the police are waiting. Another passenger saw you and Kit arguing on the boat home the night before and the police say that you had a reason to want him dead. You protest. You and Kit...

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.