Ray and Professor Gordon Hillman, an expert in the use of plants through the ages, look at the marshes and waterways which our ancestors used for travelling and as an abundant source of food. Along the way, Ray explains how to take the sting out of nettles and how to use water lily seeds as a source of carbohydrate. He then travels to the spectacular Ardeche Gorge in France where he gains special permission to take to his canoe and demonstrate spear fishing.