Little Bobby is the only child of farming parents. Their farm is isolated; Bobby's companions are a black cat, a tawny little dog named Towser, and the family's "moolie-cow." When his father buys the boy a fiddle, Bobby learns to play simple tunes upon it.
One day, his parents leave Bobby alone on the farm, as they travel to town to sell their butter and eggs. Bobby spends his afternoon weeding in the garden; at evening he takes his fiddle, and his supper of bread and milk, down to the coolness of a nearby brook. The animals accompany him. As the sun sets, the moon rises in the east, and is reflected in the water.
Bobby eats his dinner, and then plays his fiddle as the animals listen. Drowsy from his afternoon's work, Bobby dozes. The cat gets its tail caught in the fiddle's strings, and panics; it yowls and screeches as it races about trying to free itself. The startled cow jumps over the creek. Bobby, awakening suddenly, sees the cow jump over the water and the moon's reflection, and for a moment it seems to him that the cow has jumped over the moon.
The dog is also jumping and barking by this time, and sends the dish and spoon from Bobby's supper sliding into the creek. Bobby retrieves his fiddle, and finds that it has survived its rough treatment; he fetches the cow and gets the spoon and dish from the creek.
At home, Bobby lights a lamp and sits down to compose a tune about the incident. The panting dog appears to be smiling at the whole adventure. Bobby puts all of the elements of the evening into the lyric for his song.