Lila Emerson is fascinated by other people's lives. As a house-sitter, she loves looking after the glamorous, sophisticated homes she could never afford herself. And as a writer, she enjoys watching the world go by, dreaming up stories for the people she sees from her window. But then one day she witnesses something only too real - the brutal and shocking murder of a young woman living across the street in New York. And now, because of what she saw, her own life is in immediate danger from an audacious, single-minded assassin who kills for profit and for pleasure. With the police following a false lead, she is on her own. Her only hope is to team up with Ashley Archer, an artist with his own complicated reasons for getting involved.