Wales's three National Parks - the Brecon Beacons, Snowdonia and the Pembrokeshire coast - are areas of outstanding natural beauty and precious havens for wildlife. But these are fragile landscapes, dependent on us to maintain them for future generations. Dedicated wardens and rangers take on this responsibility day in, day out. This is their story. We explore how to live in Tenby and please the planners; farmers and wardens in Snowdonia reap the benefit of their partnership; and in the Brecon Beacons, Paul Sinnadurai is on a damage control exercise to ensure the delicate peat surface of Mynydd Myddfai survives the pipeline. Also, in a reflective mood, ranger Ian Meopham goes paddling amongst the seals in Strumble Head.