Luzi and sister have a secret. They know a spell, just read it and follow a snail that runs faster than a rabbit to go to the magical interstitial world. There, they experienced many incredible adventures, but what ZUI likes is an old bookstore that has been raining all the time. On this day, Luzi and her sister came to the raining bookstore and learned that the owner, Mr. Guben, was suffering from an extinction cold. They might recite the curse of extinction at any time, endangering the entire interstitial world. At this time, a mysterious girl suddenly appeared, grabbing Luzi and her sister, creating chaos everywhere...