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.