Paul Murton follows the eastward course of the river South Esk from its source in the hills above Glen Clova to the Montrose Basin, and on to the sea. Along the way he searches for Scotland's rarest plant, goes electro-fishing to discover more about the ecology and general health of the whole river system, and rides a motorbike to the ancestral home of Harley-Davidson.
Paul Murton discovers the source of the River Nith, high in a remote forestry plantation. Heading downstream, he hears the story of the Knockshinnoch mining disaster - how 116 men were saved from entombment after a massive earth collapse. He also learns about the first man to make a bicycle with pedals, heads to the riverside home of Robbie Burns and finds out how a Dumfries man helped Neil Armstrong walk on the moon.
Paul Murton explores the lower reaches of the Spey, famous for its forests, whisky distilleries and salmon as it flows north towards the coast. On the way Paul hears tales of loggers who floated timber down the river from the 17th century onwards. He also takes to the water in a canoe and discovers the rare and endangered freshwater mussels that were once harvested for their precious pearls, which adorn royal crowns.