Petronella is not an ordinary witch—because she has three sisters! And this Christmas they’ve come to stay! But what kind of Christmas mood can there be when it’s raining outside? Apparently, this year Santa Claus will have to trade his sleigh for a boat with oars! In the miller’s house, Lina and Luis are mad at each other. Each plays petty tricks on the other. Or maybe someone invisible has moved in and wants to start fights among everyone? Whoever it is, he won’t withstand four witches armed with a guidebook of rare spells! For children of middle school age.