Margherita Taylor is in Wiltshire meeting an inspirational farmer whose work with vulnerable children is having remarkable results. Keeley Donovan is down in the murky depths of a London sewer, discovering the dangers posed by our discarded cooking fat. Jules Hudson joins the fight against time and tide on the Essex coast, in a race to rescue our threatened heritage. And Hamish Thomson of the Woodland Trust pays a return visit to Paul Martin's smallholding to provide advice and assistance at a tree-planting party.