Moko is an explorer. As he travels the world continent by continent, he makes many friends and discovers many natural phenomena which sometimes delight him, and other times scare him. Each animated episode recounts an adventure and takes an "original story" approach to explaining these natural phenomena. In this episode, Moko wants to head off and tells Totemie that he must find the end of the world. But a fisherman tells them that no one will find what it is that they seek unless they have passed by the blue holes, or underwater cave. Moko doesn't understand but follows the path of a mysterious and immense blue hole in the middle of the ocean. This is when strange things begin happening. The sea is swirling and the sky changes color. Strange lights appear in front of their raft, then disappear. They get the impression that they are flying high above the ocean, then mysteriously they find themselves back on the beach. Moko remembers his first trip and thinks that this must be the heart of the ocean beating for his old friend.