Twelve-year-old Stephanie Harrington, a genetically-enhanced girl on the pioneer planet of Sphinx, bonds with a treecat, a telepathic and fully sentient animal, putting her in danger from highly placed enemies who want to ensure that the planet remains entirely in human hands.

Bell has spent his whole life -- all eleven years of it -- on Mars. But he's still just a regular kid-he loves cats, any kind of cake, and is curious about the secrets the adults in the US colony are keeping. Like, why don't have contact with anyone on the other Mars colonies? Why are they so isolated? When a virus breaks out and the grown-ups all fall ill, Bell and the other children are the only ones who can help. It's up to Bell -- a regular kid...

Pursued by power-hungry Prentiss and mad minister Aaron, young Todd and Viola set out across New World searching for answers about his colony's true past and seeking a way to warn the ship bringing hopeful settlers from Old World.