Niall Iain Macdonald and Calum Macaulay take to the water as they explore the Caledonian Canal. They cruise down Loch Ness as far as Fort Augustus, where they get on their bikes and cycle the Great Glen Way. Niall Iain joins the crew of the Vic32, Scotland's only operational puffer, at Fort Augustus. Shovelling coal is hot work, but he is still charmed by this wonderful old boat. At Gairlochy Calum, visits Achnacarry House, seat of the Cameron clan, where the Commandos honed their skills, before visiting the monument in their honour at Spean Bridge. Calum and Niall Iain both compete in the Beast Race, a 10k endurance race through water and mud on the shores of Loch Ness. They end their journey at Neptune's Staircase, Banavie, the longest set of locks in Great Britain, with a stunning view across Loch Linnhe.