From the acclaimed Mysteries of Cove series.

In the steam-powered mountain city of Cove, creativity is a crime and “invention” is a curse word. Following clues left by the notorious inventor Leo Babbage, Trenton and Kallista—Leo’s daughter—set out to defy Cove.

Trenton has a knack for all things mechanical. Kallista is the daughter of Leo Babbage, a notorious inventor who perished in an explosion. Together, they learn Leo’s secrets. The teens begin to assemble a strange machine that will threaten every truth their city is founded on—and quite possibly their very lives.