When thirteen-year-old Anna Brighton meets a great bear in the orchard behind her house, she is terrified. But when it speaks to her, she is sure she is going crazy. Then other animals start speaking to her and she slowly learns she has been chosen by the Earth to stop an evil Dark Lord from crossing through a hidden gateway from Earth's mysterious sister planet, Thera. If he gets through, he will cause death and destruction on both worlds.
Armed with growing powers she barely understands and forced to face menacing creatures sent through the gateway to destroy her town, the struggle carries Anna and her best friend Alex into Thera, where the Dark Lord, his army of man-beasts and a huge, blind tiger await them.