The poem describes Belinda, a little girl who lives with various pets - a black kitten named Ink, a grey mouse called Blink, a yellow dog called Mustard, and a dragon named Custard. While the other pets are brave, Custard is a coward who cries for a safe cage. One day while the pets are playing in a wagon, they hear a scary sound and see a pirate climbing in through the window with pistols and a cutlass, intending harm. Belinda cries for help as she and the other pets, except Custard, become frightened by the pirate intruder.