Abby and her sister, Zara, are not real people. They were made, created by pandimensional beings - the Grace - to help save space and time. The Grace gave them special powers. With just a thought they can be anywhere or when in the universe. They can affect people, see into their heads, influence their thoughts.... They’re still learning what they can do.

Now they've completed their mission, the Grace have left them to fend for themselves. The universe is dangerous, unpredictable. Abby is not so good-as-gold as she appears. Zara's already destroyed a whole world. And they've got only each other.

Part One: The Sphere. “It's great here. You can get anything!” The Sphere is a private satellite complex and offers every kind of entertainment. It doubles in size every week. They lash new hotels and casinos to the outer skin, pinning them in place with huge girders. Zara came here by mistake and was quickly caught up in the noise and excitement. It's got into her head. When her sister, Abby, comes to the rescue, Zara insists that she can't leave. What is the secret that Zara is carrying with her? Why is Abby so ill? And how long can she resist the Sphere getting into her head as well?

Part Two: The Fog. “There's no such thing as witches.” Abby and Zara find themselves in the small town of Compton in October 1912. In the local pub, they meet Nan, who offers them the local beer and then has them arrested. Something is killing the town's children, something that hides in the fog, something that prevents Abby and Zara from leaving. But Abby knows something worse is coming to the town - something that will kill them all. Can Abby and Zara prove their innocence and help solve the mystery? Or is it sometimes better not to know?

Part Three: The End. “The Grace don’t know everything. We have to do what’s right!” Abby and Zara's past is catching up with them. A man they did wrong by has hunted them down across all of time and space, just to sell them out. The space pirate Kreekpolt knows the sisters can save his daughter's life - even if it burns Abby and Zara completely away. After that, 10,000 dead souls - hungry and empty and furious - want whatever is left....