Gwilym looked at the mountains towering ahead, through which they must pass. He felt a tingle of excitement. His own life had been spent in his home valley tucked down behind the cliffs, with the sea on the other side. Droving in mountain country was dangerous, they said. Sometimes sheep were stolen by robbers. Sometimes, coming home, the drovers would be robbed of the money they were carrying. Sometimes the winter weather came early, with winds and frosts and snow on the tops. He shivered a little at the thought. Gwilym and his dog Brown are on their first trip taking his father's sheep to market. They'd be having a good time if Huw, the old shepherd, didn't always want to spoil their fun. But soon the dangers of the drovers' roads threaten to put a stop to their fun, and their lives, all together.