Coast embarks on an island-hopping adventure in Scotland around the stunning Western Isles and out to the northern outpost of Shetland. On Eriskay, Nick has a close encounter with a family of dolphins and he is invited to a golden wedding anniversary where the whole island gather to party. On the Isle of Lewis, Nick meets the leader of the Guga Hunters, a small band of men following the age-old tradition of catching young gannets. Neil Oliver explores the tragic shipwreck of the Iolaire. On New Year's Eve 1918, over 200 servicemen returning home from the First World War, drowned within sight of their homes on the Isle of Lewis as the Iolaire was torn apart in ferocious seas. Hermione Cockburn is on an expedition to Staffa. Armed with an acoustics expert, a violinist, and a starting pistol, she conducts a curious experiment to explore the remarkable musical quality of Fingal's Cave. Miranda Krestovnikoff is on Shetland to search for the shy otters who struggle to survive on this wild coast. Tessa Dunlop is on a deep-sea survey ship to see how the epic voyage of HMS Challenger first revealed the astonishing secrets of life in the depths of the world's oceans.