Paul explores the upper reaches of the mighty River Tay, beginning with a flight in a microlight over the river's source, high above Ben Lui. Returning to earth, Paul goes underground to explore an active gold mine beside the river. Canoeing downstream, he meets the chief of Clan Macnab on a sacred island in the river.
A boat trip on Loch Tay recalls the glory days of steamers, before Paul meets up with experimental archaeologists building a replica Iron Age village on the shores of the loch. In an ancient woodland, he meets up with a tree lover who makes fabulous furniture from the oak that grows beside the river. Journey's end is the centre of the elusive heart of Scotland.