The Ruby in the Smoke (Sally Lockhart Quartet)

"Beware the seven blessings" When she first utters there words, sixteen-year-old Sally Lockhart doesn't know their meaning. But when an employee of her late father hears them, he dies of fear. Thus begins Sally's terrifying journey into the seamy underworld of Victorian London, in search of clues that will solve the puzzle of ther father's death. Pursued by villains and cutthroats at every turn, she at last uncovers two dark mysteries. One involves the opium trade; the other, a stolen ruby of enormous value. Sally soon learns that she is th the key to both- and that it's worth her very life to find out why.