Penny Smith, Tony Christie, Tessa Sanderson, Diarmuid Gavin and Tom Conti tackle a new waterways adventure on the Canal du Midi, a 17th-century feat of engineering. They find their new boats at the marina in Sete on the coast of the Mediterranean. The banter begins with their first decision over who gets which boat, resulting in repelling of boarders, cauliflower cannonballs and the confiscation of keys. The famous five tangle with local fishermen and have confused communication with bridge controllers, but eventually leave port and set off across France's largest lagoon, the Etang du Thau.