'Ancient Roman province of Britannia, AD 84.
'Eleven-year-old Livia has known no other life than travelling alone with her father, a respected eye doctor, for her mother died when she was born. But now her father has died too and Livia has to keep a promise she made him: to take a mysterious key to her estranged uncle Marcus. She has no idea what it opens, and she has not seen her uncle for years.
'But she is determined to keep her promise and sets out with the key, her old horse Pegasus and her father's medicine kit, only to learn that her uncle has left for a friend's place in Viroconium, further north. By the time she reaches that town, her uncle has gone, and his friend, Aurelius Silvius, won't tell her where he is. It seems her quest is at an end: until a boy named Mato informs her that he knows where her uncle is headed. But he refuses to tell her unless she promises to take him with her.
'As Mato and Livia journey on the trail of Livia's uncle, they begin to suspect that the secret of the key is extremely dangerous. But just how dangerous, they will soon learn. And now Livia and Mato must keep their wits about them or pay with their lives. But figuring out just who is friend, and who is foe, in this game of cat and mouse, is the greatest challenge of all.'
Source: Publisher's blurb.