Umberland (The Everland Trilogy, Book 2‪)‬

Forget the story of Alice's Adventures in Wonderland you know. Because in Umberland, the only way out is into the madness.Gwen, Pete, and the others have escaped from Everland. But the safe haven they hoped to find at Alnwick Castle doesn't exist. With the Queen of England on her deathbed, Duchess Alyssa has stepped in, but things have gotten worse as the cure Doc created for the Horologia virus has mutated, accelerating the disease. The only possible solution he can think of is to go back to the virus's origin: an extinct poisonous apple. Legend has it a tree bearing the apple might be found at the center of a deadly labyrinth hidden deep within Germany. A place that no one in their right mind enters. With no other options, Alyssa sets out with only her sword, her wits, and the help of Maddox Hadder, a wild boy who oversees the castle gardens. To get to the center of the maze, she'll be forced to battle monsters more terrifying than her darkest nightmares. But can anyone truly survive the madness of the maze? And what if there's no apple to be found there?