Petra Kronos has a simple, happy life. But it’s never been ordinary. She has a tin spider named Astrophil who likes to hide in her hair and give her advice. Her best friend can trap lightning in a glass sphere. And Petra’s father is able to move metal with his mind. He has been commissioned by the prince of Bohemia to build the world’s finest astronomical clock. Then Petra’s father returns home—blind. The prince has stolen his eyes, enchanted them, and now wears them. Petra doesn’t know why, but she does know this: She will go to Prague and steal her father’s eyes back. When she finds out that her father’s clock has the power to destroy the world, Petra realizes she may never make it home alive.