Michael Portillo's Scottish coastal railway journey reaches Invergordon on the Cromarty Firth, the third great inlet on the northeast coast of the Highlands. He arrives on Britain's northernmost railway, the Far North Line, and heads straight onto the water to explore a former oil drilling rig now moored in the firth. It's easier said than done; Michael is hoisted into the air by crane as he clings to a 'personnel basket'. The decline of the oil industry since its peak in the 1990s means that rather than drilling wells, this rig now caps old ones, securing them with cement. Michael helps to assemble a pipe that could stretch up to two miles long. Michael's next stop is Fearn, from which he heads to the mudflats and saltmarsh of Nigg Bay and its Global Energy Park. Michael hears how both the area and personnel have moved away from oil and gas to renewables and marvels at the colossal scale of the wind turbines he sees being readied for transport offshore. He discovers the blades for one tower are longer than a standard football pitch! On the shore of the Dornoch Firth, Michael helps to reintroduce his favourite delicacy to the firth's shallow waters. Oysters were plentiful in this region for thousands of years, but their great popularity during the 19th century led to a catastrophic decline. Now oysters are beginning to flourish again, and Michael joins Herriot Watt University's team effort to establish 200,000 oysters at Dornoch within the next three years. Michael's next stop is the Glenmorangie Whisky Distillery, also located on the banks of the Dornoch Firth. The science and art of whisky production are revealed to Michael as he tours the distillery.