Button and Popper tells the story of a family of pixies—mother, father, and twelve children—who live in an apple tree. They enjoy its warmth and shelter, eating apple pie all spring and summer long. But when fall comes, the leaves begin to drop and the apple tree becomes a cold and wet place to live. Twin brothers Button and Popper decide to find their family a new home, but when they trek into the city and start inquiring about an apartment with room for twelve children and their parents, people laugh in their faces or politely excuse themselves.
Luck strikes when, through a most fortunate mix-up at the market, the pixies find themselves in the home of Professor Pilli. When he hears their story, he invites them to look after his house while he’s away at the South Pole. When the rest of their pixie family finds out the good news, everyone is relieved and happy again.