Marcus and Delilah couldn’t be more different. He is as big as she is tiny. As angry and lost as she is tremendous and brave. But they share a dream: to own a dog of their own.

When a mystery pup turns up in the empty house next door, Marcus can’t believe his luck. He visits him every night and names him Moon Dog. But it’s soon clear that Moon Dog is in danger, and when Marcus and Delilah discover a dark secret it will test their bravery and their friendship.

Can they work together to save their dream dog? Billy and his friends must set off on a dangerous adventure that will take them to the heart of the Dragon Realm. But can they save the dragon and human worlds from destruction?