12-year-old twins Matt and Emily Calder are Animare: they can bring art to life and enter paintings at will. They must do everything in their power to prevent a breach in Hollow Earth: a supernatural place that holds all the demons, devils and creatures ever imagined.
The explosive sequel to Hollow Earth. Supernaturally gifted twins Matt and Emily Calder must stop those who seek to unlock Hollow Earth with a magical bone quill key, unleashing a monstrous army of beasts. Hunting the quill, the twins use their powers to time-travel to the Middle Ages. There they are forced to make a terrible choice: save their father, or save the world.