The series concludes with a 200-mile journey down England's east coast, from the river Humber to the river Thames and into the heart of the capital.
Neil Oliver visits the birth place of his seafaring hero Lord Nelson, exploring the Norfolk shoreline that inspired young Nelson to greatness and the curious ship-shaped pond he dug at the family home while not fighting the French. Neil visits Sutton Hoo, where in 1939 an Anglo-Saxon burial ship was unearthed to become one of Britain's most important archaeological sites. The ornate find of a warrior's helmet gave a face to the Germanic tribes that founded England.
On the shingle bank at Orford Ness, Alice Roberts leads a team trying to recreate the original war-winning experiment which proved that radar would work. Alice visits Bawdsey Manor, where the first British radar station was built, to meet two women posted there during the war to operate the early warning system. It was 'hush-hush' work that they kept completely secret - even from close family.
Off the Norfolk coast, Nick Crane explores the remarkable lost world of 'Doggerland', the home of the early Britons, lost to sea some 10,000 years ago as sea levels rose after the last Ice Age.
Miranda Krestovnikoff wades out in the mud of 'The Wash', a vast tidal feeding ground for migrating birds. Miranda discovers the ingenious strategies that different birds use to fatten themselves up on the seafood of the Wash.
Enthusiasts spend fortunes to restore the wrecks of sailing boats which used to work around the Thames Estuary. To investigate the appeal of the glorious Essex Fishing Smacks, Mark Horton joins a crew on competition day to discover how the elegant yacht-like design is perfectly adapted to dredging for oysters.