New York Times bestselling author Sarah Beth Durst takes readers on an unforgettable journey full of whimsy and adventure as a young girl and her imaginary friend set off to save a magical factory full of fantastic creatures.

It's really very impolite to ask anyone to risk life, limb, and extra limbs without giving them a choice.

Shy daydreamer Amelia has been looking forward to this day for as long as she can remember: the day she, as a ten-year-old, finally gets to enter the magical Imagitorium and create her very own imaginary friend.

But when she walks out of the Creation Room with Ruru, a fluffy, bearlike being with butterfly wings who gives excellent hugs, and into a scene of pure chaos, she quickly realizes that something's gone very wrong. The Imagitorium is so much bigger than anyone outside knows, filled with dragons and sea monsters and candy cyclones, and now it's starting to fall apart. The Caretaker is missing, and it's up to Amelia to find her.

Amelia knows that she's never been a hero, but... maybe she can still help?