A young woman, Natalie Meadows, jumps from Blackfriars Bridge, escaping from the horror she has just witnessed. But she is rescued and feels duty-bound to find out who murdered her best friend, the music hall star Nellie Warwick, and why. Natalie reinvents herself as Flora Thorne and finds a position as housemaid to the Reverend Wallace and his daughter. From the sanctuary of their home, she is able to investigate the circumstances of Nellie's murder...