On the hunt for the mysetious Ninth Legion of the Roman Army, the Doctor, Nardole and Bill go their own ways in the search for these men. Whilst seperated, Bill and the Doctor encounter both the Celts and the Romans whom are hiding away from a species of interdimentional, light eating monsters. Bill convinces the Romans to try and get to safety through an underground tunnel system whilst The Doctor makes the Celts prepare for anonther boiught with the beast. After evading the creature, the Celts and Romans make a truce in the hopes to escape their battle with the creature and head back to their respective countries in peace. Sadly the only way to fully seal the gateway between the dimensions is for the celtic leaders and the Roman Ninth Legion to join together and fight the light eaters in the gateway for the rest of their lives.