De Li finds a frog in her garden. When the frog sees her, it makes a strange sound. De Li thinks the sound is very funny. She brings the other Piplings to see the frog and asks it to make the sound again. But the frog is quiet. The Piplings and then the cheebies all try lots of different things to persuade the frog to make the sound. But the frog remains silent. Finally, the cheebies ask De Li what she did when she first found the frog. De Li remembers. She fell over and made a funny noise herself. When she does the same thing again, the frog makes his noise again. They all realise that the frog is laughing and they all laugh together!