The sentinel stood on the wall and did not look at the city behind her because the city was not her responsibility. Her responsibility was the dark before the gates, the spaces where things moved just beyond the torchlight's reach. She had been standing watch for six years without break. The relief crew would come at dawn, would take the wall while she slept in the guard house, and then she would return to stand through the next night and the night after that. This was Helm's covenant, eternal watchfulness with no rotation from the duty. In the darkness, something moved. Not a threat. She could read the darkness now the way others read books. It was a fox, moving through the scrub toward the city perimeter. She made a note in the watch log. Everything that moved was recorded. A younger guard came to relieve her weariness with fresh drink and a meal. He asked if she had seen anything. 'Movement at the east corner,' she said. 'Fox. No threat.' He nodded and withdrew, and she returned to the darkness, and her eyes never wavered. The city slept behind her, and the people slept because she stood watch, and Helm's eyes, which never closed, looked down and saw her standing at the boundary between sleep and danger, and was satisfied. The night continued, and she stood, and in a thousand other towers and walls, other sentinels stood as well, an unbroken circle of vigilance that held the darkness at bay...