The Ocean…the world’s largest ecosystem. Almost 3 million square kilometres of water surrounds China, from the magnificent coral reefs in the South China Sea to the deep-sea world of the Okinawa trough in the East China Sea, and the sea pasture of Yellow Sea and Bohai. In this episode, we will see the rich and colorful underwater world maintain by coral reefs in the South China Sea, and how Chinese scientists helping the coral reef to restoration vitality; We will follow the underwater robot "discovery" to explore the mysterious undersea world in the East China Sea which is deep more than one thousand meters, and exploring species from the deep ocean: mussel, porcelain crabs, Alvin shrimp and a mixture of lava and seawater that provide them with organic matter. We will go to Yellow Sea and Bohai which closely related to humans life, to see how people living in the seaside to catch jellyfish, sea cucumber, seaweed and seaweed, and learn to living in harmony with the ocean.