Imagine a world where everyone is born with a 'skin' name. Without skin you cannot learn, you are not permitted to marry, and you grow up an outsider amongst your own people. This is no future dystopia. This is Celtic Britain. It is AD 43. For the Caer Cad, 'skin' name determines lineage and identity. Ailia does not have skin; despite this, she is a remarkable young woman, intelligent, curious and brave. As a dark threat grows on the horizon - the aggressive expansion of the Roman Empire - Ailia must embark on an unsanctioned journey to attain the knowledge that will protect her people, and their pagan way of life, from the most terrifying invaders they have ever faced...and it is this unskinned girl who will come to hold the fate of her people in her hands.