The war party fanned out across gorse, the long grass bending under the strong night breeze. The moon had broken free of the clouds; the sky was star-lit and clear. They hurried forward like a wolf pack eager for the kill. Their chieftain was moving to the front when he heard the clink of chain, the creak of harness, the neigh of a horse. He froze stock-still like a hunting dog, eyes peering through the darkness. Shapes were approaching, horsemen spreading out into an arc; a number carried flaring torches. The chieftain narrowed his eyes, wiping away the lime-mingled sweat. He tried to count. Eight, maybe nine horsemen, perhaps even more, were moving slowly towards his war party of about thirty men.
The Picti was a veteran. He might outnumber the enemy, but these were Catephracti, mailed, mounted troopers, highly disciplined and dangerous on such terrain. He screamed a warning, pointing back to the gates, and broke into a run, gesturing at his men to follow. Those quickwitted amongst his warriors had already sensed or seen the danger. Others were too drunk or confused. They only realised the ambush they had walked into when the formidable line of horsemen moved into a trot, then a full charge, the air riven by a hideous rumble of hoofs, the sounds of the night drowned by the clatter of weapons and the heart-chilling war cry of the Roman cavalry. The horsemen swept in, cloaks billowing, swords rising and falling. The tribesmen scattered. Out in the open they were doomed. If they fled towards the wall the riders would pin them against it and cut them down. They had to break free of the wall, retreat into their own territory.