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, intrigued by the name given to the mountains, "the hills of the round earth," Moko sets off to find out if the earth is really round. An old man tells him if he keeps walking straight, he could travel round the earth and get back to his starting point. Moko follows his advice but since he never got the feeling he was walking around a sphere, he still thinks the earth is flat.