Matt Baker and Charlotte Smith head to the Peak District to celebrate the 70th anniversary of the UK's first national park.Matt joins a pioneering scheme to restore ruined farm buildings and meets 'legend' of the Peak District Gordon Miller, one of the area's early rangers and a last link to those who brought about the national park. Charlotte channels her inner artist to help create a giant anniversary art mural and records the special sounds of the park's waterways. Sean Fletcher meets a 'tyre runner' using the Peak District's hills to help his mental health. Meanwhile, as some of his traditional crops fail, Adam takes a glimpse at what the farming of tomorrow might look like, and Joe Crowley investigates new pollution laws causing controversy in the countryside.