Cruise! The word alone made you dream: wide horizons, exotic stopovers, luxury and idleness... The promise is as vast as the blue planet.

Rescued by dolphins 22 April 2014. Long-distance swimmer Adam Walker crosses the Cook Strait in New Zealand. Everything is going well until he sees a great white shark in his wake. Frightened, he desperately tries to flee when dolphins appear and surround him and keep the shark away. They will "escort" him like this for three hours! From the coasts of France to those of the United States, via South Africa and New Zealand, we will be amazed by the protean intelligence of the dolphin. Stars or guinea pigs?

We are rich and... We don't know! Rich in everything that nature has invented over millions of years and that we earthlings have not been able to see. Most of these treasures can be found in a huge and unexplored liquid desert: the sea! Food, health, energy, housing and lifestyle... Very quickly, it will be from her that our daily life will come. From the beaches of Brittany to the depths of the abyss, via the hostile waters of Antarctica, Thalassa criss-crosses the world to meet those who have found their Eldorado and who, tomorrow, will make us "merrians".

Fishing in the middle of a storm: On board the "Bara Pemdez", a 24-metre-long trawler, Yannick the skipper and his 4 sailors keep watches, day and night relentlessly. They live by the rhythm of the trawl and resist everything. A report by Antoine Mora, Jean Christophe Cheneau and André Laffont The connected oyster? A spy to fight against theft! A report by Laurent Cadoret and Christophe Castagne Cliff fisherman: Abderrahmane the tightrope walker risks his life 30 meters above the waves. A report by Pierre Lalanne and Lionel Langlade A gifted worm: The arenicole, an ordinary marine worm, lives and breathes by the beach to the rhythm of the tides. By studying its extraordinary oxygenation system, the French biologist has developed a universal blood

Adventure, in all its forms and in all latitudes, is at the heart of this evening! Like these "new" holidaymakers who choose to live an experience that is very different from their daily lives. Or the one experienced for twenty years by the expeditions launched in search of the wrecks of La Pérouse's ships, finally reported in the Pacific. And what can we say about the "supreme" adventure that the cream of French sailors is living in Bermuda in their quest for the Holy Grail: the América's Cup! And let's not forget the Sultanate of Oman, where the adventure is human, sporting, and revolutionary with young women who remove their veils to be able to hoist... the sails!

Head west, to meet the islanders of Ushant, Sein, Groix and Quéménès, off the coast of Brittany. We discover their daily life before leaving far, far away, from the Iroise Sea. Destination Spitsbergen, a land forged by ice and wind at the gateway to the Arctic Ocean. Ten years ago, Soizic and David, newlyweds, landed on a small piece of land in the middle of the Iroise Sea. With no running water or electricity, the islet of Quéménès consisted of only a few old farm buildings, distant vestiges of a past activity. The Conservatoire du littoral, owner of the place, has entrusted them with a mission: to bring nature back to life, to harvest, to raise animals and to welcome the public in guest rooms. Ondine Morin is one of the most famous figures on Ushant, the westernmost island of Finistère, a wild land anchored 20 km from the mainland. A pioneer, this thirty-year-old was one of the first to decide to stay on her native island.

The host sets off to discover Polynesia, with its exceptional ecosystem. Contents: The Blue Paradise. Encounters with avid divers who try to catch a glimpse of extraordinary sea creatures. This is the case of Denis, a cameraman, who dreams of witnessing the mating of tiger sharks • The farmers of the lagoon. Portrait of the Laiza family, who make a living from fishing on the Tuamotu atoll • Papy Tavi, the va'a in their veins. At the age of 72, Papy Tavi still competes in va'a races, the traditional canoe of the Pacific islands. With 30,000 practitioners, the discipline is the number one sport in Polynesia.

The show's teams conducted the investigation into the shrimp market. Raised or caught, the small crustacean is indeed one of the most consumed seafood products in France. Contents: Madagascar: shrimps in the shade of the mangrove. Meet Amyne Ismail, who started an eco-friendly aquaculture system • Tromso: with the lords of the Barents Sea. Voyage aboard the "Ocean Tiger", an ice-breaking shrimp vessel. This vessel fishes for northern shrimp, a very popular species • Wreck hunter: between passion and thrill.