This Grand Tour begins in the hills above Glen Clova, on a mountainous plateau known as the Mounth. Following the South Esk downstream, Paul enters picturesque Corrie Fee, where he scrambles on the cliffs with two botanists, searching for Scotland's rarest plant. Back on the South Esk, he goes electro-fishing to discover more about the ecology and general health of the whole river system.
Running out of riverside paths, Paul takes to the road for a few miles and rides a motorbike to the ancestral home of Harley Davidson. Later he discovers how social distancing in the 17th century enabled traders to ply their wares during the plague in Brechin, Scotland's smallest city. Where the river enters the saltwater Montrose basin, Paul learns how plans to transform the tidal basin into a Dutch-style polder for agriculture were scuppered by a storm witch – or was she just a scapegoat for competing interests?
During the Second World War, the Norwegian navy was stationed in Montrose. Their mascot, a huge St Bernard dog called Bamse, became a war hero and a national celebrity. Paul pays homage to the giant dog with a visit to his statue before ending his journey down the South Esk at the river mouth, where a lighthouse stands guard over the rocks of Scurdie Ness.