Actor and comedian Griff Rhys Jones sets out on an adventure to explore how rivers have influenced, nurtured and powered our lives throughout history. From the raging torrents of Scotland to the reflective flatlands of East Anglia, Griff barges, canoes, swims and sails his way along a hidden network which has been the lifeblood of Britain. Griff starts his journey with the wild rivers of Scotland. He travels east, upstream from Kinlochleven, into one of the most remote areas of the country, then follows the fast and furious course of the water downstream to Perth. He milks fish for their eggs, goes canyoning, and canoes a fast-flowing river that fallen pine trees have turned into an obstacle course.

Griff Rhys Jones sets out on an adventure to explore how rivers have influenced, nurtured and powered our lives throughout history. From the raging torrents of Scotland to the reflective flatlands of East Anglia, Griff barges, canoes, swims and sails his way along a hidden network which has been the lifeblood of Britain. Griff's journey continues as he travels from Liverpool to the Humber along Britain's working waterways. He attempts to swim the almost-freezing Mersey, before travelling by barge through the canal network and going underground to help clean up Britain's secret rivers. He is also a guest at Chatsworth, and gets to grips with their unusual plumbing as the water that feeds the toilet hurtles down from a distant reservoir on the estate.

Griff Rhys Jones explores how rivers have influenced, nurtured and powered our lives. From the powerful torrents of Scotland to the flatlands of East Anglia, he barges, canoes, swims and sails his way along this often hidden network which has been the lifeblood of the country. Griff follows the mighty Severn from its source in the Welsh hills to the estuary 200 miles later. He also follows its neighbour, the Wye, which starts and finishes nearby. From drinking water to the iron ore that furnished the industrial revolution, he finds that rivers have provided for mankind over tens of thousands of years. On his journey Griff attempts to bog snorkel, meets druids for a ritual water blessing, sleeps in a hermit's cave and builds a willow coracle similar to ones used on the river thousands of years ago.

Griff Rhys Jones explores how rivers have influenced, nurtured and powered our lives. From the powerful torrents of Scotland to the flatlands of East Anglia, he barges, canoes, swims and sails his way along this often hidden network which has been the lifeblood of the country. Griff is in London. But instead of working his way up the Thames, he heads off for another river which has been vital in the city's history: the Lea. He meets the Sicilian cucumber-growing community of Essex, sails a gunpowder boat and trains with a team of veteran rowers. Plus he discovers the vital balance between water coming in to a city and its waste going out.

Griff Rhys Jones comes to the end of his adventure along the rivers which have influenced, nurtured and powered our lives. From the raging torrents of Scotland to the working waterways of northern England; from the mystical West to the urban South East, Griff has paddled, sailed, barged and sometimes swum his way along this often hidden network which was once the lifeblood of the country. The last leg of his journey takes Griff to East Anglia, the part of the country he knows best. He sees a traditional way of life still surviving in the man-made ditches of the Fens, revisits the romantic sailing boats of his childhood on the Broads, and follows the beautiful River Stour, winding its way through Constable country and finally bringing him home. At the end of his journey, Griff assesses how the conflicting interests of farmers, anglers, canoeists, industrialists and nature lovers can be reconciled to ensure the future of Britain's rivers.