The four celebrities pootle on along the Kennet and Avon canal from Bradford on Avon to Devizes. However, the quartet are having rather different barging experiences. While Nigel Havers and Debbie McGee are enjoying a lovely, relaxed journey aboard their barge over on the other boat actor Simon Callow is becoming increasingly exasperated with Lorraine Chase's chatter. Simon lets his love of history steer the way to a forgotten waterway, but all four of the celebrities allow their sightseeing antics to get the better of them when they find themselves late to their mooring - forcing them to wait until sunrise for the final furlong. The narrowboat enthusiasts will have to work together to negotiate the magnificent Caen Hill Flight - 29 consecutive canal locks climbing the hill.