Almost everybody who has grown up in Chicago knows about the Thorne Rooms. Housed in the deep inside the Chicago Art Institute, they are a collection of 68 exquisitely crafted miniature rooms. Each room is set in a different historic period, and every detail is perfect. Some might even say, the rooms are magic.

But what if on a field trip, you discovered a key that allowed you to shrink so that you could sneak inside and explore the rooms' secrets? What if you...

Chicago sixth graders Ruthie and Jack think they've learned everything about the magic of the Art Institute's Thorne Rooms. But the magic starts to act strangely when Ruthie and Jack discover two rings that are out of place--and out of time--and a portal that shouldn't be open but somehow is. Ruthie and Jack follow the clues to seventeenth-century England and the Brownlow...