The final episode of this series sees Ellie Harrison and Adam Henson explore the hidden highlands of Scotland. Inspired by suggestions from viewers of Countryfile, Adam and Ellie meet people living in Britain's countryside who have extraordinary stories and stunning sights to share. The pair also reveal some secrets of their own. Adam climbs the fearsome, secret side of Ben Nevis, the north face, a spectacular rock ascent onto which few tourists venture. Adam joins a mountain guide to tackle this hidden route to the summit, but the route is far from the only secret they find along the way. Adam also discovers the ruins of a remarkable abandoned weather station. Ellie probes a monster mystery at the heart of Britain's deepest water, Loch Morar, the secret sister of the world-famous Loch Ness. The stunningly beautiful Loch Morar is so deep that it could even hide the Eiffel Tower, but Ellie meets locals who believe the water actually conceals a monster, known as Morag. The most extraordinary map of Scotland is also revealed, overgrown and hidden in the landscape. In the heart of the Highlands, Adam is delighted to discover a cattle ranch that allows him to live out a boyhood dream; while on the Black Isle Ellie visits the mysterious and atmospheric Clootie Well. It's been a shrine to healing since Celtic times, but why are its ancient rituals still popular today? Together Ellie and Adam also go hunting for Bonnie Prince Charlie's secret hideaway, a tiny but timeless cave in the very same landscape where commando warfare was invented during the Second World War. And they conclude their journey of discovery with a magical ride on the real Hogwarts Express.