Five Children and it

Curious to see if people on the other side of the globe walk upside down, Robert, Anthea, Cyril, and Jane start digging a hole to Australia. They don't get too far, however, before they dig up a furry brown creature with bat's ears. It is a Psammead, an ancient Sand-fairy. The Sammyadd, as the children call it, grumpily tells them that he is obliged to grant their wishes, because making people's wishes come true is what Sand-fairies do. However, there is one catch: The wishes come undone at sunset. No matter how carefully the children plan, their wishes keep backfiring, and they realize that you have to be careful what you wish for--you may get it.