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 explores the new Olympic site through which the Lea flows, and discovers the vital balance between water coming in to a city and its waste going out.