It was the very end of autumn, and Flax and Lily were busy making blankets for the voles in the High Hills. Mr. Apple had to deliver the blankets to them before the cold weather set in, and Wilfred Toadflax was eager to go along. He was convinced there was gold to be found in the hills beyond Brambly Hedge, and this was his chance to discover it.

Everything went according to plan until Wilfred scrambled up a rock face and couldn't get down. The mist began to rise, and soon Mr. Apple and Wilfred were engulfed in a thick white fog, unable to find their way home...