In AD 60 the Roman Empire occupies Britannia, destroying its ancient culture. Under the leadership of Boudicca, the Iceni rise up against Nero's forces but it is a losing battle. Yet the Druids are masters of nature, and in a final desperate strategy to avoid slavery, the priests summon their greatest magic to open a portal into an alternative world. One last Celtic tribe, the Ordoveteii, race to cross the threshold...