Joybubbles recounts the story of the imaginary friend of a girl named Sheralyn. Sheralyn was a part of a play group Joybubbles went to. She had been adopted out of a children's hospital as a young child.
One day, on the way to a parenting meeting for her adopted mom, Sheralyn had to use the bathroom so they stopped at a gas station. After continuing on almost all the way to the destination, Sheralyn suddenly realized she had left her imaginary friend Bumpo at the gas station. They turned around and drove all the way back, ten or twelve miles, to get Bumpo. Sheralyn called her adopted mom "mommy" for the first time, and from then on they celebrated the anniversary of the finding of Bumpo instead of the official adoption date.