During winter, Iolo finds himself in blizzard conditions on the Black Mountains, foxes survive in an emptied reservoir below the Beacon’s highest peak, Iolo meets canal repairers, a traditional hedge layer, a winter visitor from Russia also known as the ‘butcher bird’ that catches its prey and impales them in a ‘larder’ for storage and later feeding, Wales’ only wild red deer herd, the tallest waterfalls in southern Britain, the deepest cave systems in Europe and a horse woman leading timber

During spring, water voles are found living near the National Parks’ biggest lake, there’s trout fishing on the Usk – the Beacon’s largest river, peregrines nesting in an old quarry, there’s an old gunpowder works in a secluded gorge in waterfall country, and on the western fringe of the Park – Wales’ biggest Iron Age Hill Fort.

The summer is the peak period for visitors in the Park. Iolo travels on the Brecon Mountain Railway, he joins the Beacons’ mountain rescue team on Fan Gyhirich – one of the highest peaks. The uplands also get a makeover by hauling wool on horse back to place in peat for protection. Iolo also learns about herbal medicine on Mynydd Myddfai – a centuries’ old tradition in the area.

Iolo Williams ends his journey in the autumn. It’s a time when the National Park is at its colourful best. The fall sees thousands of fieldfares arriving from Europe who are escaping from the colder continent to the relatively less severe climate of Wales. In a water mill in the Usk Valley, bats feed up for the last few nights before they disappear to hibernate in caves. Water birds are also arriving on Talybont Reservoir ready for winter. Iolo looks for cave spiders and discovers hundreds of sea trout migrate upstream to the Carmarthenshire uplands.