One moonlight night Amber sees a strange creature called Sunflower through her bedroom window. Sunflower invites her to visit its friends called Moonies, that live in caves. The friendly creature persuades her to watch the Moonies dancing.
Soon afterwards a fearsome monster flies overhead and the terrified Moonies take shelter in their homes, followed by Amber and Sunflower who are chased through a forest by the Wortoron, a terrifying enemy of the Moonies. They discover that one of their friends called Fuzzy has been carried off by the monster. Amber and some of the Moonies which can fly set off to rescue their friend.
Amber rides on the back of a winged creature called Horse and they follow the Wortoron to its mountain lair. Amber and her brave helpers have many scary adventures in underground caves, lakes, and dark forests, and eventually win a battle with the monsters high in the sky.
Ever since Amber was little she was fascinated by the moon. Even now that she was eight going on nine she often lay in bed at night when it was full moon watching it gliding through the clouds like a ghostly saucer. It was even scary, and she often wondered if perhaps there were creatures living up there that might come sliding down moonbeams to the earth at night and wander around looking for children to eat.
Then one night she was dozing off after watching the moon, which always made her sleepy, when there was a tap on the window pane next to her bed. She sat up with her heart thumping. Her sister Tao was asleep in bed on the other side of the room but Amber decided not to wake her. It was probably just a twig blown by the wind that caused the tapping, she told herself, and there was no need for alarm. So she settled down and was beginning to fall asleep when the tapping started again this time louder.
Amber jumped up and went to the window holding a hockey stick, which she always kept next to her bed to chase away ghosts. She peered through the window pane. Outside was a silvery light, the leaves on the trees shining and the grass on the lawn glistening. It was scary, with everything quiet, and nothing moving. Her face was pressed against the glass so she could see better. But there was nothing that could have caused the tapping. So she climbed back into bed, feeling angry at being disturbed when she had to get up early next morning for school.
She was just comfortable when there it was again, tap, tap, tap. As she got near the window she saw something really weird looking at her through the glass pane.