As autumn arrives, Moss, Sorrel, Burnet and Dormer decide to return home to Ash Row to unravel a riddle that might explain why their kind are fading from the Wild World. When you're only one-hand high, it's a journey filled with both danger and delight: golden leaves, shiny conkers and the brightest of berries, but also storms and the first frost of winter. They have friendship, good sense and humour on their side, but will it be enough to secure a future for the Hidden Folk? Or will they need to go further, and find a way to work with the most unreliable of creatures, humans?