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 and Mei-Lei are resting as the day is fading. Suddenly, they hear a strange sound coming from behind the mountain that resonates throughout the village. The two friends go off to find the source of this strange sound and what they see surprises them. Two men are blowing into what look like long horns while others walk along with them and sing. They head back towards their village, confident that they have solved the mystery of the echo.