On a cold, fretful afternoon in early October, 1872, a hansom cab drew up outside the offices of Lockhart and Selby, Shipping Agents in the financial heart of London, and a young girl got out and paid the driver.

   She was a person of sixteen or so - alone, and uncommonly pretty. She was slender and pale, and dressed in mourning, with a black bonnet under which she tucked back a straying twist of blonde hair that the wind had teased loose. She had unusually dark brown eyes for one so fair. Her name was Sally Lockhart; and within fifteen minutes, she was going to kill a man.