12 year old Downie, known as "Jackdaw", the best thief in London, is desperate to save his helpless brother and sister from the brutality of Ivory Sal and her two vicious sons. His skills draw the attention of young Frank Verney, who serves Walsingham, Queen Elizabeth's fanatical spy-master.Diverted by the lovely daughters of Black Kate, Frank rebels against the lies, double dealing and blackmail of the Protestant wolves at Elizabeth's court as they close in on Mary, Queen of Scots. Her friends make romantic, doomed plans to rescue her, but who is urging them on? Knowing who is friend or foe can mean life or death to Frank, Jack and Susannah in their quest to save the threatened queen; and Ivory Sal complicates matters further with her determination to get her revenge on the elusive Jack. As events intensify so does the danger for the three young friends.