Flora Maguire's life is perfect - a beautiful home in Belgravia teeming with servants, a loving husband, and new baby Arthur to enjoy. But when she is invited to tour St. Philomena's Children's Hospital in a deprived area near London's newly-built Tower Bridge, she is shocked. Because there she uncovers a scandal with a dark heart - poor children are going missing from the hospital. The police seem either unable or unwilling to investigate, so Flora teams up with the indomitable matron of the hospital, Alice Finch, to try to get to the bottom of it. Soon Flora is immersed in the seedy, dangerous underbelly of criminal London, and time is running out to save the children. Will they get to them in time, or was their fate decided the day they were born...