What if the world holds more dangers?and more wonders?than we have ever known? And what if there is more than one world? From Heather Dixon, author of the acclaimed Entwined, comes a brilliantly conceived adventure that sweeps us from the inner workings of our souls to the far reaches of our imaginations.

Jonathan is perfectly ordinary. But then?as every good adventure begins?the king swoops into port, and Jonathan and his father are enlisted to find the cure to a deadly plague. Jonathan discovers that he's a prodigy at working with a new chemical called fantillium, which creates shared hallucinations?or illusions. And just like that, Jonathan is knocked off his path. Through richly developed parallel worlds, vivid action, a healthy dose of humor, and gorgeous writing, Heather Dixon spins a story that calls to mind The Night Circus and Pixar movies, but is wholly its own.

He must master the art of illusion to save his family. But what if the illusions are more real than he knows?

• Magic and Science: Jonathan must choose between his father's careful research and the dangerous, seductive power of fantillium, a chemical that bends reality itself.
• A High-Stakes Plague: The mysterious Venen is spreading, a plague that targets only women?and with Jonathan's mother and sister infected, the search for a cure is personal.
• An Aerial City: From the icy, steam-powered walkways of Fata Morgana, Jonathan is swept into the heart of the empire's political intrigue.
• Parallel Worlds: The secrets of fantillium are deeper than anyone knows, opening doorways to other realities where danger and discovery await.