Precocious ten-year-old Vanessa Dudley-Morris knows lots of secrets. In 1949 when she and her family are forced to move into two rooms on the second floor of 519 Jarvis Street in Toronto, a genteel but somewhat rundown rooming house owned by a reclusive pianist, she learns a lot more.
Despite the family's drastically reduced circumstances, her parents struggle to keep up their old standards. Threatened by blindness due to an eye condition, Vanessa is kept at home, tutored by an erratic succession of eccentrics, some with questionable credentials. Consequently, she spends a lot of time alone, wandering the dim corridors of the old house, silently listening at doors and watching the odd characters who live there. She becomes fascinated by a mother and son who move into a room on the third floor. Eventually she agrees to take secret notes from the son to his mysterious friend at her church, unwittingly unleashing a chain of events that leads to tragedy.