The Mirror of Naples

During his routine morning rounds, Sir Cedric Mallory discovers a man in the Woolsey Rooms who is not supposed to be there before opening hours. When he informs him of this, the man turns to face him and Mallory sees that he is none other than the Queen's own private secretary, Sir Peregrine Lloyd. Mallory also notices that Lloyd has a dagger shoved deeply into his stomach area.
"The Mirror of Naples: Preserve it," Lloyd manages to rasp before falling to the floor, dying.
Thus begins the convoluted investigation into the murder of Sir Peregrine, and Detective Chief Inspector, Mick Chandra and his partner, Detective Elizabeth Chang, are assigned to this high-profile case. What did Sir Peregrine mean by referring to the Mirror of Naples? Mick learns that the Mirror was a priceless jewel once in the possession of Henry VIII, but was thought to have disappeared long ago. But did it?
The case takes Mick and his partner to the far reaches of Buckingham Palace, the Tower of London, Windsor Castles, as well as Ukraine and Russia. Was the Mirror fenced to purchase nuclear warheads by a hostile foreign power? Was it stolen by a greedy collector? Or does it really still exist at all?
Be prepared to be surprised.