This is book number 9 in the Wayward Children series.
Portals and danger, and a girl who can find both in the next book in the Hugo and Nebula Award-Winning Wayward Children series from Seanan McGuire.
Antsy is the latest student to pass through the doors at Eleanor West's School for Wayward Children.
When the school’s (literally irresistible) mean girl realizes that Antsy's talent for finding absolutely anything may extend to doors, Antsy is forced to flee in the company of a small group of friends, looking for a way back to the Shop Where the Lost Things Go to be sure that Vineta and Hudson are keeping their promise.
Along the way, they will travel from a world which hides painful memories that cut as sharply as its beauty, to a land that time wasn’t yet old enough to forget—and more than one student's life will change forever.
Mislaid in Parts Half-Known is a story that reminds us that getting what you want doesn't always mean finding what you need.