Ellie Harrison and Matt Baker are in Cambridgeshire, where Matt looks at a huge project to turn a quarry into the UK's biggest reed bed. Thousands of tons of sand and gravel are being shifted at Ouse Fen to create the perfect habitat for wildlife, including one of the UK's rarest birds, the bittern. Matt is also on hand to help release some fish into specially-created pools. Ellie is with a team from Cambridge University whose work is throwing new light on the secret life of truffles. She also takes a walk in the woods with botanical artist Caroline Henricksen, who reveals a world of wonder beneath Ellie's feet. Wildlife cameraman Richard Taylor Jones witnesses a wildlife spectacle of a lifetime, Adam Henson meets a young farmer making a go of it in the New Forest, plus the latest instalment from the young vets. Tom Heap has an exclusive interview with Bill Gates about why he's making the most of British agricultural expertise.