Britannia, 45 AD: In the shadow of Stonehenge, Vespasian's brother, Sabinus, is captured by druids. The druids want to offer a potent sacrifice to their gods - not just one Roman Legate, but two. They know that Vespasian will come after his brother, and they plan to sacrifice the siblings on a summer's day. But to whom will they be making this sacrifice? What were the gods of this land before the Celts came? Only the druids still hold the secret and...