Geographer Nicholas Crane presents a 13-part journey around the coast of the United Kingdom, uncovering stories that have made us the island nation we are today. This leg takes him along Scotland's west coast. Nicholas begins aboard the classic yacht Crunneaig and discovers why this diverse coastline makes for some of the most exciting sailing in the world. Alice Roberts finds a new pride on the river Clyde, as she joins the launch of the 11,000 tonne war ship, The Cardigan Bay Historian. Neil Oliver joins the crew of the trident submarine HMS Vanguard as they embark upon a series of sea trials. Mark Horton is in the Sound of Jura feeling the force of the famous Corryvreckan whirlpool, the third largest whirlpool in the world. Miranda Krestovnikoff sails around the Hebridean islands of Rhum and Eigg on the trail of the elusive Minke whale. And Mark and Neil recreate the rocket mail service, proposed 70 years ago as an inter-island communication service.