The Tale of Time Warp Tuesday

In the second of The Zephram Tales (after The Month of Zephram Mondays), Tom, Lizzie, Ned and Nell, the Royal Quadruplets and non-magical Heroes of the magical Kingdom of Zephram, have settled back into their same old boring routines after the excitement of saving Zephram and the rest of the world from evil Prince Persius.
Then they suddenly realize just why everything is so incredibly boring: it's because everyone's repeating the same day, over and over again!
Tom, Lizzie, Ned and Nell are the only ones who know what's happening, and it looks like they're the only ones who can do anything about it. But why has it happened? How are four non-magical children going to start the magical world turning again? And what will they find out about themselves in the process?