3 magical girls who can transcend worlds, brought together in a sanitarium that is not as it appears. Adventures ensue. I adored it, it was such candy reading. I will say that if you haven't read and loved Oz, Wonderland, and Peter Pan, and a few others, you may not enjoy this book. It's very highly literary. Kind of a mid-grade version of Jasper Fford's Eyre Affair. I also don't love the way the girls themselves, despite being the main characters, aren't artistically portrayed that differently from one another. It makes the storytelling less clear than it should be that all have sort of generic white girl facial features. Still, a very fun quick read.