The mysterious and tumultuous land of 43AD Britannia is occupied by many warring tribes, until the invasion of a foreign army sparks chaos and allegiances. Celtic rivals Kerra (Kelly Reilly) and Antedia (Zoe Wanamaker) must face the oncoming Roman invasion led by Aulus Plautius (David Morrissey) as it seeks to dismantle the Celtic Resistance.
In series premiere, The Celts of 43AD Britannia are a divided and warring group of tribes. But all tribal disputes are sidetracked with the arrival of General Aulus Plautius leading his army of Roman invaders. The invasion is only foreseen by rogue Druid Divis, where on his secret mission to overthrow the Romans, he finds an unlikely ally in a young Celt girl, Cait.